Any US settlement or resolution of the conflict that enables Iran to control traffic through the Strait of Hormuz would represent a major US defeat and set a precedent with critical implications for global trade, given the strait's role as a critical energy chokepoint. Iran has repeatedly claimed sovereignty over the Strait of Hormuz, but Iran has no legal claim to the strait, which international law defines as an international waterway.[1] Iran has repeatedly attempted to regulate traffic through the strait by directing vessels through Iranian territorial waters, extracting fees, and attacking and threatening maritime traffic.[2] Recent Iranian proposals to the United States have also implicitly demanded that the United States and international community recognize Iran's “control” over the strait.[3] Iran has offered to “let” vessels transit the strait in these proposals, but Iran's “letting” traffic through the strait implies that Iran can “let” traffic through an international waterway.[4] These proposals are consistent with persistent Iranian messaging throughout the war that Iran seeks to impose a new status quo for transit through the strait.[5] Any US acceptance of Iran's ability to regulate transit would undermine the principle of freedom of navigation through the Strait of Hormuz and enable Iran to condition access to the strait on compliance with its demands, thereby enabling Tehran to exert persistent pressure on the global economy and the United States and its allies.
Iran is attempting to establish a protection racket in the Strait of Hormuz by granting priority transit to vessels that pay fees and comply with Islamic Revolutionary Guards Corps (IRGC) protocols as part of its effort to try to consolidate control over the strait. A senior Iranian official told CNN on April 18 that vessels that pay “security fees” and comply with the IRGC’s protocols will receive priority transit through the Strait of Hormuz, while those that refuse to pay will face delayed passage.[6] Iran has reportedly charged vessels around $2 million USD to transit the strait.[7] Extracting fees from commercial vessels enables Iran to earn income amid the United States’ efforts to impose economic pressure on Iran through its blockade of Iranian ports.
The IRGC has also continued to prevent non-Iranian-linked vessels from transiting the strait. Bloomberg reported on April 18 that at least five liquefied natural gas (LNG) tankers reversed course after Iran warned the vessels’ captains that it had closed the Strait of Hormuz.[8] No LNG tankers have exited the Strait of Hormuz since the war began in February.[9] Iranian media separately reported on April 19 that the IRGC forced the Botswana-flagged Meda and the Angola-flagged G Summer to change course after the vessels attempted to cross the Strait of Hormuz.[10] Commercially available shipping data indicates that the G Summer later transited the Strait of Hormuz via the Iranian-approved route on April 19.[11]
US forces seized an Iranian-flagged container ship for the first time during the war. US President Donald Trump announced on April 19 that the US Navy's USS Spruance, a guided missile destroyer, intercepted the Touska in the Gulf of Oman, disabled the vessel's engines, and commandeered the ship after the Iranian crew refused to return to port.[12] US forces seized the Touska after it attempted to pass the US blockade line. The United States previously sanctioned the Touska, which is owned by the Islamic Republic of Iran Shipping Lines.[13]
Commercially available shipping data indicates that the US Navy also forced at least three Iranian or Iranian-linked ships to change course toward Iranian ports on April 19. The vessels include the US-sanctioned Guinea-flagged Raine tanker, the Iranian-flagged Shamim container ship, and the Hong Kong-flagged Flora tanker, which was previously Iranian-flagged.[14]
At least four Iranian or Iranian-linked ships appear to be attempting to pass the US Navy's blockade line. US officials have stated that the United States will interdict vessels beyond the blockade line. The vessels include the Iranian-flagged Artman container ship, the Liberian-flagged Basel, the Marshall Islands-flagged CECI, and the Vietnam-flagged NV Aquamarine.[15] Both the Basel and CECI originated from Iranian ports, while the NV Aquamarine is under US sanctions and is blacklisted by United Against Nuclear Iran.[16] US Chairman of the Joint Chiefs of Staff Dan Caine and Defense Secretary Pete Hegseth said on March 16 that US forces will interdict any ship that crosses the blockade line, which runs diagonally across the Gulf of Oman from Ras al Hadd, Oman, to the Iran-Pakistan border.[17]
The US Navy is reportedly conducting naval mine-clearing operations in the Strait of Hormuz to restore the official transit route through the strait amid the Navy's continued blockade of Iranian ports. The Wall Street Journal reported on April 19 that the US Navy is using uncrewed surface vessels (USV) and submersible drones to clear an unspecified number of Iranian naval mines in the Strait of Hormuz.[18] Clearing Iranian naval mines from the Strait of Hormuz is necessary to restore trust in the safety of the official traffic separation scheme, where Iran has reportedly laid the mines.[19] Military analysts told the Wall Street Journal that US Navy USVs and submersible drones could identify naval mines in the strait relatively quickly and that the US Navy could then deploy a second wave of drones to conduct explosive ordnance disposal operations.[20] Iran deployed a limited number of naval mines in the Strait of Hormuz in March 2026, but a former US Navy official told the Wall Street Journal that Iran laid fewer mines than expected due to US military pressure that constrained Iran's use of large mine-laying ships.[21]
US Vice President JD Vance, US Special Envoy to the Middle East Steve Witkoff, and Jared Kushner are expected to travel to Islamabad, Pakistan, to engage in negotiations with Iran on April 21.[22] ISW-CTP has not observed any Iranian sources confirming Iran's participation in the negotiations as of 6:00 PM ET on April 19, however. Unspecified Iranian sources, including an unidentified member of Iran's negotiating team, told Iranian state media on April 19 that Iran does not currently have any plans to participate in the next round of talks.[23] IRGC-affiliated media reported on April 19 that there are no clear prospects for future negotiations due to the United States’ demands and continued naval blockade of Iranian ports.[24] ISW-CTP assessed on April 18 that the IRGC has likely consolidated control over Iran's negotiations policy.[25] Iranian officials echoed similar sentiments to Pakistani officials on April 19.[26] The 14-day ceasefire between the United States, Israel, and Iran is set to expire on April 22.[27]
A statement released by Iranian-backed Iraqi militia Kataib Hezbollah on April 18 appears to confirm that IRGC Quds Force Commander Brigadier General Esmail Ghaani discussed preparations for renewed conflict with the United States and Israel during his meetings with Iraqi militia leaders in Baghdad on April 18. Ghaani may have specifically discussed enhancing coordination between Iraqi militias and other Axis of Resistance groups against the United States, Israel, and the Gulf states in the event of renewed conflict. Kataib Hezbollah Security Chief Abu Mujahid Aasaf issued a statement after Ghaani’s visit to Baghdad that called for increased coordination between the “resistance forces and other parties,” which implicitly refers to military cooperation.[28] The “other parties” may refer to other Axis of Resistance groups such as the Houthis or Hezbollah. Iranian-backed Iraqi militias have launched drone and rocket attacks targeting US and foreign interests in Iraq, as well as the Gulf countries, during the war.[29] Iran, Hezbollah, and the Houthis may have attempted to coordinate some attacks during the war, but ISW-CTP has not observed any instances of Iranian-backed Iraqi militias coordinating their attacks with other Axis of Resistance groups.[30]
Incomplete reporting about the damage that the US-Israeli combined force inflicted on Iran's ballistic missile and drone programs precludes the development of a quantitative assessment about the threat that Iranian missiles and drones still pose. Multiple US officials told the New York Times on April 19 that Iran retains around 40 percent of its attack drones, around 60 percent of its missile launchers, and around 70 percent of its missile stockpile.[31] The officials stated that the 60 percent of missile launchers includes around 100 launchers that Iran has dug out from underground facilities since the ceasefire went into effect.[32] ISW-CTP previously assessed that Iran is exploiting the ceasefire to reorganize and regenerate its ballistic missile forces on a tactical level, including by clearing debris from tunnel entrances to retrieve missile launchers from underground missile bases.[33] The recent assessments about Iran's remaining offensive capacities do not specify whether the launchers that Iran has dug out from underground facilities are intact or operational. Shockwaves from combined force strikes may have damaged launchers stored in underground facilities without directly hitting them. The recent assessments also do not specify what kinds of launchers Iran has retrieved. Iran possesses different kinds of launchers for ballistic missiles with different ranges. These gaps preclude the development of a quantitative assessment about the current status of Iran's missile program.
https://understandingwar.org/research/middle-east/iran-update-special-report-april-19-2026/
updated link https://www.iranintl.com/en/liveblog/202604194357
Iranian Parliament Speaker Mohammad Bagher Ghalibaf appears to be engaged in a serious intra-regime debate with Islamic Revolutionary Guards Corps (IRGC) Commander Major General Ahmad Vahidi and other senior regime officials opposed to negotiations with the United States. Ghalibaf publicly defended negotiations on Iranian state television on April 18, arguing that diplomacy with the United States, alongside military power, is necessary to secure Iran's objectives.[1] Ghalibaf also reportedly criticized hardline officials, including Supreme National Security Council (SNSC) member Saeed Jalili and hardline parliamentarian Amirhossein Sabeti, for their opposition to negotiations during a meeting with advisers, but his criticisms were likely implicitly directed at Vahidi. US officials separately told Axios on April 20 that the US negotiating delegation thought it was “negotiating with the right people“ in Islamabad on April 11 and 12 but that the IRGC effectively told the Iranian negotiating delegation upon their return to Tehran that they ”don't speak for” the IRGC.[2] Senior regime officials, including former IRGC Intelligence Organization Chief Hossein Taeb, reportedly called the Iranian negotiating delegation back to Tehran after it surpassed its mandate.[3] A second US official told Axios that “we aren't sure who's in charge and neither do they.”[4] This report is consistent with ISW-CTP’s assessment that there is a division between Vahidi and his inner circle and members of Iran‘s negotiating team over Iran's negotiations policy.[5] This report is also consistent with ISW-CTP’s assessment that Iranian Supreme Leader Mojtaba Khamenei has not played the role of cohering and arbitrating between various factions as his father used to do, which has likely exacerbated intra-regime fighting.[6]
Vahidi appears to have the upper hand over Ghalibaf at the moment. Vahidi is reportedly the only Iranian official with direct access to Supreme Leader Mojtaba Khamenei and is serving as a conduit for relaying key decisions to other regime officials, according to Israeli media on April 19.[7] Israeli media also reported on April 19 that Iranian officials‘ inability to contact Mojtaba is a significant obstacle to continued US-Iran negotiations.[8] Ghalibaf’s push for diplomacy and apparent effort to reach a deal may also be a bid to protect his domestic position and maintain credibility.[9] Ghalibaf reportedly fears that both his and Araghchi’s positions are at risk if the IRGC consolidates control.[10] Ghalibaf’s removal as the parliament speaker would represent a major defeat for Ghalibaf and his domestic positions and signify a victory for Vahidi. These reports are consistent with ISW-CTP’s ongoing assessment that Vahidi and members of his inner circle have likely consolidated control over not only Iran's military response in the conflict but also Iran's negotiations policy.[11]
US and Iranian delegations will reportedly meet in Islamabad, Pakistan, for a second round of talks in the coming days.[12] Two US officials speaking to the New York Times on April 20 stated that US Vice President JD Vance will travel to Pakistan on April 21. Two Iranian officials told the New York Times that Iranian Parliament Speaker Mohammad Bagher Ghalibaf, who led the Iranian delegation in the first round of talks, would attend the upcoming talks if Vance attended.[13] US and Iranian demands appear to have largely stayed the same. US officials speaking to the Wall Street Journal stated that the US delegation is pushing for the immediate reopening of the Strait of Hormuz, a pause in Iranian uranium enrichment for at least 20 years, and the removal of Iran's highly enriched uranium (HEU) stockpile from Iran.[14] The Wall Street Journal reported that Iran's demands are Iranian ”control” over the strait, the lifting of sanctions on Iran, and a shorter pause in uranium enrichment.[15] US President Donald Trump previously indicated that a pause in enrichment would be insufficient to meet US demands.[16]
The Khatam ol Anbia Central Headquarters claimed that the April 19 seizure of the Iranian-flagged, US-sanctioned Touska by the US Navy violated the US-Iran ceasefire.[17] The spokesperson for the Khatam ol Anbia Central Headquarters, which is functionally controlled by the IRGC, warned on April 19 that Iranian forces will respond to the US seizure of the Touska and asserted that the United States had “violated the ceasefire.”[18] Unspecified security sources told Reuters that the Touska was likely transporting dual-use items from China to Iran.[19] The sources added that the Touska had previously transported dual-use items to Iran.[20] US Central Command (CENTCOM) told United Kingdom Maritime Trade Operations (UKMTO) on April 16 that it considers raw materials such as oil, iron, steel, aluminum, and certain civilian goods with both civilian and military applications to be “conditional contraband.”[21] CENTCOM also defined electronic components, computer systems, machinery, and power generation equipment as “conditional contraband.”[22] The Touska visited the port of Zhuhai in China in March.[23] Zhuhai Port is considered a loading port for chemicals, including missile fuel precursor sodium perchlorate, according to the Washington Post.[24] The Wall Street Journal reported that a subsidiary of the US-sanctioned Islamic Republic of Iran Shipping Lines (IRISL), Rahbaran Omid Darya Ship Management, owns the Touska.[25] Two vessels owned by Rahbaran Omid Darya Ship Management transported approximately 1,000 tons of material used in missile propellant in 2025, according to the Wall Street Journal.[26]
Iran likely continued to prevent non-Iranian-linked vessels from transiting the Strait of Hormuz. Commercially available shipping data indicates that Iran forced the Marshall Islands–flagged Capetan Costas S and the Curaçao-flagged Lumina Ocean to alter course after they attempted to transit the strait via the Iranian-approved route following their departure from Basra, Iraq.[27] These incidents follow a similar incident on April 19, when the IRGC forced the Botswana-flagged Meda and the Angola-flagged G Summer to change course after the vessels attempted to cross the Strait of Hormuz.[28]
The Iranian Parliament is attempting to formalize Iranian “control” over the Strait of Hormuz.[29] Iranian parliamentary legislation requires additional approval from the Guardian Council before it is enacted into law.[30] Iranian media reported on April 19 that Iran's parliament is drafting a bill that would ban Israeli-linked vessels from transiting the Strait of Hormuz, require vessels from “hostile countries” to obtain approval from Iran's Supreme National Security Council to transit the strait, and bar states that “caused damage” to Iran from transiting the strait until they paid reparations to Iran.[31] The Iranian parliamentarian who announced the bill said that Iran would allocate some of the revenue from Strait of Hormuz transit fees to fund the Iranian armed forces’ reconstitution under the bill.[32] This report follows a similar report on March 26 that Iran's parliament was working to formalize a process for vessels to pay Iran in exchange for safe passage through the Strait of Hormuz.[33] Iranian Parliamentary National Security and Foreign Policy Commission head Ebrahim Azizi told the BBC on April 20 that Iran will “never” be ready to give up its “control” of the Strait of Hormuz.[34] Azizi added that Iran's “control” of the strait will be signed into law, in reference to the Iranian parliamentary bill described above.[35] Azizi characterized Iran's “control” of the strait as “one of [Iran's] assets to face the enemy.”[36] These comments reflect the Iranian regime's view that the Strait of Hormuz is Iran's main point of leverage vis-a-vis the United States.
CENTCOM announced on April 20 that US forces have directed 27 vessels to change course since the start of the blockade.[37] These vessels likely include the US-sanctioned Guinea-flagged Raine tanker and the Iranian-flagged Artman container ship, which both changed course after approaching the US blockade line on April 19, according to commercially available shipping data.[38] Both ships likely sought to pass the US blockade line before being forced to change course.[39]
ISW-CTP is unable to assess whether two vessels that originated from Iranian ports and passed the US blockade line are in violation of or exempt from the US Navy's blockade. Commercially available shipping data shows that the Liberian-flagged Basel and Marshall Islands–flagged CECI, which departed from Bandar Imam Khomeini Port, Khuzestan Province, on April 15 continued to transit along the Omani coast toward separate ports in Brazil on April 20.[40] CENTCOM announced on April 14 that it would not allow vessels to enter or exit Iranian ports.[41] UKMTO reported on April 16 that vessels carrying humanitarian goods are exempt from the blockade, however.[42] It is unclear what cargo the Basel and CECI are transporting.[43] CENTCOM has noted that all Iranian vessels, vessels under US sanctions, and vessels suspected of carrying contraband are subject to the right of visit and search, regardless of their location.[44] ISW-CTP previously noted that US forces can interdict vessels almost anywhere in international waters until they reach their final destination.[45]
A third vessel, the Vietnam-flagged NV Aquamarine, has also continued sailing, but this ship is likely exempt from the US blockade and considered “neutral shipping,” given that it departed from the United Arab Emirates (UAE) and is not under US sanctions.[46] ISW-CTP incorrectly attributed United Against Nuclear Iran's blacklisting of the NV Aquamarine as evidence that the vessel was an Iranian-linked vessel attempting to pass the US Navy's blockade line on April 19.[47]
Satellite imagery confirms that the US-Israeli combined force conducted multiple strikes on a reported IRGC command center in the Jamaran complex in northern Tehran Province.[48] The strikes occurred before the ceasefire. An Iranian OSINT analyst assessed that the United States struck the site with massive ordnance penetrator bombs.[49] Iranian media previously described the site as the most important and “strategic” broadcast transmitter in Iran.[50] The analyst claimed that the site also serves as a surveillance, signal-jamming, and command center for the IRGC.[51] Fox News, citing unspecified high-level sources, reported on April 6 that the United States struck an underground IRGC headquarters in Tehran, which the analyst assessed was referring to the strike on the Jamaran complex.[52] The analyst claimed that the strike targeted a meeting of at least 50 IRGC officers at the underground complex.[53] ISW-CTP cannot independently verify that the targeted site was an IRGC command center, or that IRGC officers were meeting at the site at the time of the combined force strikes.
Iran reportedly planned to conduct covert sabotage operations against Israeli-linked sites, energy infrastructure, and other unspecified sites in Azerbaijan in recent weeks.[54] An Israeli military correspondent reported that Mossad and Azerbaijani authorities thwarted several Iranian sabotage attempts and planned attacks in Azerbaijan “several weeks ago.”[55] Mossad stated that an Iranian-backed militant cell was preparing to target the Israeli Embassy in Azerbaijan, a synagogue in Baku, and the Baku-Tbilisi-Ceyhan oil pipeline with improvised explosive devices (IED) and drones.[56] Israeli airstrikes at the start of the war killed the senior IRGC leaders behind these planned operations, including Unit 4000 Chief Rahman Moghadam, IRGC Intelligence Organization Chief Majid Khademi, and covert operations official Mohsen Suri, according to Israeli media.[57]
The IRGC Intelligence Organization's covert operations Unit 4000 also reportedly smuggled drones through Turkey and conducted reconnaissance against US forces at Incirlik Airbase in Turkey.[58] Israeli intelligence reported that a Unit 4000 officer coordinated the smuggling of drones from Iran to Cyprus via Turkey.[59] The same officer also reportedly headed operations to gather intelligence on US forces at Incirlik Airbase in southwestern Turkey.[60]
Emirati state media separately reported on April 20 that Emirati security forces arrested 27 members of a group with connections to the Iranian regime and external actors who were planning to conduct terrorist attacks.[61]
Lebanese and Israeli officials will meet in Washington, DC, on April 23 for the second round of direct ambassador-level talks.[62] Lebanese and Israeli officials met in Washington, DC, on April 14 for the first direct talks between the two countries in over 30 years.[63] Lebanese Ambassador to the United States Nada Hamadeh Moawad and Israeli Ambassador to the United States Yechiel Leiter will attend the talks.[64] It is unclear which US officials will attend the talks at the time of this writing. A Lebanese official told the Associated Press on April 20 that the upcoming talks will focus on “solidifying” the 10-day ceasefire and the logistics of future negotiations.[65] A Lebanese ministerial source previously told Saudi media that Lebanese officials’ top priority is to request an extension of the temporary ceasefire.[66] A senior Israeli political source recently told Israeli media that Israel assesses that it will need to agree to a ceasefire extension in Lebanon in the next few days.[67] The proposed extension period would reportedly range from 10 days to one month.[68] Israel and Lebanon's current 10-day ceasefire is set to expire on April 26.[69] These preparatory and logistical meetings aim to lay the groundwork for Israel and Lebanon to have direct negotiations in the future over long-standing issues, such as Israel's presence in Lebanese territory and Hezbollah disarmament.[70]
https://understandingwar.org/research/middle-east/iran-update-special-report-april-20-2026/