US Central Command (CENTCOM) announced that no vessels have breached the US blockade on Iranian ports since CENTCOM implemented the blockade on April 13.[1] CENTCOM implemented a blockade on April 13 against all vessels transiting to or from Iranian ports. The US blockade on Iranian ports does not have a defined geographic boundary, and the United States can interdict vessels almost anywhere in international waters until they arrive at their final port. US forces have previously demonstrated their ability to interdict vessels in international waters.[2] US officials told the Wall Street Journal on April 14 that US forces will likely attempt to intercept or “quarantine” any vessels that violate the blockade in the Arabian Sea to limit the threat of attacks from the Iranian coast.[3] Vessels transiting the Strait of Hormuz are therefore not automatically breaching the US blockade. Commercially available maritime data indicates that at least eight vessels departed the Strait of Hormuz, including six Iranian or Iranian-linked vessels, on April 14. One of the vessels, the US-sanctioned Rich Starry oil tanker, departed from Amjan Port in the United Arab Emirates (UAE) on April 13.[4] Other Iranian or Iranian-linked vessels, including the Elpis and Christianna, also left the strait after departing Iranian ports.[5] Commercially available maritime data also indicates that at least nine vessels entered the Strait of Hormuz, including three Iranian or Iranian-linked ships. One of the entering vessels was the Ocean Energy cargo ship, which docked at Iran's Bandar Abbas Port on April 13.[6] It is unclear whether this vessel was exempted from the blockade. Reuters reported that a US military notice sent to mariners exempts humanitarian shipments to Iran from the US blockade.[7] CENTCOM also announced that six merchant vessels complied with the US direction to return to an Iranian port in the Gulf of Oman.[8] CENTCOM has not interdicted any vessels at the time of this writing.
It is also unclear whether any of the vessels that left Iranian ports on April 14 were authorized to do so under CENTCOM’s “limited grade period.” United Kingdom Maritime Trade Operations reported on April 13 that CENTCOM granted “neutral vessels” currently docked at Iranian ports an unspecified grace period to depart. The complexity and variety of factors involved in the blockade, including determining vessels’ origin and destination and whether vessels are considered “neutral”, make it premature to try to assess whether some vessels have gotten through the US blockade.
The United States’ decision not to renew a 30-day sanctions waiver for Iranian oil exports, which is set to expire on April 19, will further constrain Iran's ability to export oil in addition to the US blockade on Iranian ports.[9] Two US officials told Reuters on April 14 that the US Treasury Department will enforce sanctions on Iranian oil after April 19.[10] US Treasury Secretary Scott Bessent also told reporters on April 14 that the US blockade on Iranian ports will ensure that no vessels from the People's Republic of China (PRC) are “able to get their [Iranian] oil.”[11] The PRC purchases more than 90 percent of Iran's oil exports.[12] A sanctions-focused US analyst estimated on April 13 that a successful blockade on Iranian ports would cost the regime around $435 million USD per day, leaving Iran with few alternatives to export and import goods.[13]
Iran is reportedly considering temporarily pausing shipments to avoid testing the US blockade on Iranian ports and raising tensions ahead of possible talks, according to a person familiar with Iranian decision-making on the Strait of Hormuz speaking to Bloomberg on April 14.[14] Iran would only be able to pause shipments for a limited period of time before it would start to run out of room to store oil. A sanctions-focused analyst reported on April 13 that Iran's onshore oil storage capacity is 13 days, after which Iran would have to shut down its oil fields, potentially causing long-term damage to the oil fields.[15] Iran's limited storage capacity highlights the difficult position the US blockade has put Iran in. Iran appears to have three other courses of action that it could take to respond to the US blockade on Iranian ports. It is unclear which course of action Iran will pursue at this time. The courses of action include:
Iran could agree to a deal acceptable to the United States, which would likely require Iran to make concessions on its nuclear program and other issues.
Iran could attempt to run the blockade, a move that would almost certainly result in a US response and possibly the seizure of Iranian vessels central to Iran's oil trade.
Iran could restart or widen the conflict, although it is unclear whether a resumption of the conflict would necessarily end the US blockade on Iranian ports.
Iranian Supreme Leader Adviser Mohammad Mokhber warned that Iran will “open new fronts” and “increase economic pressures” on US allies and regional countries in response to the US blockade on Iranian ports, likely to try to coerce the United States to end its blockade. Mokhber may have been referring to the Houthis, which have not conducted attacks on international shipping in the Red Sea during the war thus far. Arab officials told the Wall Street Journal on April 14 that Iran is pressuring the Houthis to “close” the Bab al Mandeb Strait.[16] Saudi Arabia has urged the United States to end its blockade on Iranian ports and return to negotiations due to concerns that the blockade could cause the Houthis to resume attacks on shipping in the Red Sea and Bab el Mandeb Strait, according to the Arab officials.[17] Saudi energy officials told the Wall Street Journal that the Houthis have sent guarantees that their fighters will not attack Saudi Arabia or its ships passing through the Bab el Mandeb, however.[18] Previous Houthi attacks on shipping between 2023 and 2025 sharply increased shipping costs and contributed to global inflation.[19]
US President Donald Trump stated on April 14 that the United States and Iran may hold another round of talks in Islamabad, Pakistan, “over [the] next two days.”[20] A senior Iranian source told Western media on April 14 that the United States and Iran are keeping April 17 through 19 open for possible talks, but that no date has been confirmed.[21] Trump did not specify who would lead the US delegation in a potential second round of negotiations. US Vice President JD Vance, who led the US delegation in the first round of negotiations on April 11 and 12, told Fox News on April 14 that Iran moved closer to the US position but “didn't move far enough.”[22] Two senior Iranian officials and one US official told the New York Times that Iran responded to the US demand for a 20-year moratorium on uranium enrichment with a pause “for up to five years.”[23] Iran's willingness to pause enrichment for five years would represent an Iranian concession and notable inflection in Iran's position. Vance also said that the Iranian delegation was “unable to cut a deal” and instead had to return to Tehran to get approval from “the Supreme Leader or someone else.”[24] Vance's statement is consistent with CTP-ISW’s assessment that the United States is negotiating with a de facto committee composed of competing political, military, and security factions, rather than a unified delegation with a clear mandate and unified positions.[25]
https://understandingwar.org/research/middle-east/iran-update-special-report-april-14-2026/
Iran Update Special Report, April 15, 2026
US naval forces continued to enforce the blockade on Iranian ports. US Central Command (CENTCOM) reported on April 15 that no vessels had breached the blockade on Iranian ports during the first 48 hours of enforcement.[1] CENTCOM stated that nine vessels complied with the US direction to turn around and return to Iranian ports or coastal areas.[2] CENTCOM added that US forces have halted economic maritime trade to and from Iran and are prepared to act against any vessels attempting to violate the blockade.[3] Additional CENTCOM reporting indicates that the US forces redirected at least one Iranian-flagged cargo vessel after it departed Bandar Abbas, Hormozgan Province.[4]
The United States has reportedly set two preconditions for another round of negotiations: first, Iran must fully “reopen” the Strait of Hormuz, and second, the Iranian negotiating delegation must have “full authority” to finalize a deal.[5] Iran has not conducted any kinetic activity targeting international shipping since April 7.[6] Iran does not need to conduct attacks against vessels to maintain the threat to international shipping, however. The decision for vessels to transit the strait is for the shipping companies, which will likely be hesitant to move vessels through the Strait until Iran provides reassurance that it does not pose a threat to their vessels and cargo.
The second precondition, which demands that Iran‘s delegation have “full authority“ from Iran’s senior leadership (including the Islamic Revolutionary Guards Corps (IRGC)) to finalize a deal, corroborates ISW-CTP’s assessment that the United States is negotiating with a divided council of hardliners and pragmatists rather than a singular, unified authority.[7] US Vice President JD Vance stated on April 14 that he believed that the Iranian negotiators in Islamabad wanted to make a deal, which implies that he assesses that the hardliners in Tehran were responsible for Iran’s reticence to make a deal.[8] Anti-regime media separately reported on April 14 that Iranian Supreme National Security Council (SNSC) Secretary General Mohammad Bagher Zolghadr was furious when Iranian Foreign Affairs Minister Abbas Araghchi allegedly appeared open to compromising on halting Iranian funding for the Axis of Resistance at the US-Iran negotiations in Islamabad on April 11.[9] Zolghadr then reportedly briefed Araghchi’s “deviation” to senior leadership, including by sending messages to IRGC officials and Supreme Leader Mojtaba Khamenei’s close affiliate Hossein Taeb, which resulted in the leadership ordering the delegation to leave after 21 hours of negotiations.[10] Zolghadr was one of the founding members of the IRGC Quds Force and helped establish some of the groups that now comprise the Axis of Resistance.[11] Unspecified mediators speaking to the Wall Street Journal on April 15 confirmed that Zolghadr has been “highly influential” in Iranian decision-making in US-Iran negotiations.[12] These reports follow previous anti-regime media reports on April 10 that IRGC Commander and key decisionmaker Major General Ahmad Vahidi pushed to get Zolghadr on the Iranian delegation to Islamabad, but the delegation leaders Araghchi and Parliament Speaker Mohammad Bagher Ghalibaf pushed back due to Zolghadr’s lack of diplomatic experience.[13] The senior leadership’s response to withdraw the delegation after Araghchi’s reported openness to discussing Iran’s support for the Axis of Resistance shows how unwilling the hardliners are to compromise on Iranian positions and how much sway they have over Iranian decision-making.
Some Iranian officials have signaled different levels of willingness to compromise on Iran’s nuclear program in negotiations with the United States. These statements, at least to some extent, reflect internal disagreement over Iran’s negotiating position. Iranian Deputy Parliament Speaker Ali Nikzad stated on April 15 that Iran will not negotiate its right to enrich uranium.[14] Former hardline President Mahmoud Ahmadinejad appointed Nikzad to several ministerial posts while he was president, and Nikzad later served as campaign chairman for former hardline President Ebrahim Raisi in the 2017 election.[15] His relationship with hardline figures suggests that Nikzad may similarly hold hardline, anti-Western views. Iranian Foreign Ministry spokesperson Esmail Baghaei adopted a slightly more flexible tone and stated on April 15 that Iran is willing to discuss “the level and type of enrichment.”[16] Baghaei emphasized that Iran must retain the ability to enrich uranium based on its ”needs,” however.[17] Foreign Minister Abbas Araghchi leads the foreign ministry and is more pragmatic than some Islamic Revolutionary Guard Corps (IRGC) officials involved in negotiations, which may make him more open to supporting limited concessions (see above). Two senior Iranian officials separately told the New York Times on April 13 that Iran told the United States that it is willing to pause enrichment for up to five years.[18] These differences likely reflect the presence of competing factions in Iran with divergent objectives in negotiations, which ISW-CTP previously assessed will likely complicate efforts to reach a negotiated agreement.[19]
Israeli Defense Minister Israel Katz stated on April 14 that the United States and Israel have decided that removing the enriched uranium from Iran is a “threshold condition” for ending the US-Israeli campaign.[20] Iran offered to downblend its highly enriched uranium instead of handing over its highly enriched uranium (HEU) stockpile during US-Iran talks on April 11 and 12.[21] ISW-CTP previously assessed that Iran presumably seeks to dilute rather than hand over its HEU stockpile so that it could re-enrich this stockpile at some point in the future.[22]
The US Treasury continues to sanction the Iranian oil trade as part of the broader US economic pressure campaign against Iran.[23] The US Treasury sanctioned 29 targets, including three individuals, 17 companies, and nine vessels on April 15, which are tied to Iranian oil smuggling and associated financing networks.[24] The US Treasury Department designated individuals and companies involved in shipping, logistics, and financial facilitation activities that support Iranian oil exports and sanctions evasion.[25] The Treasury stated that these networks operate within the broader shipping empire of Hossein Shamkhani and generate revenue for the Iranian regime and its regional proxies, including Hezbollah.[26] Hossein is the son of former Iranian Defense Council Secretary Ali Shamkhani.[27] The United States sanctioned Hossein and his multinational shipping network in July 2025 for generating tens of billions of dollars in revenue for the Shamkhani family and the Iranian regime.[28] The Treasury separately reported on April 14 that it is maintaining “maximum pressure” on Iran and is prepared to impose secondary sanctions on foreign financial institutions that continue to support Iranian activities.[29] The Treasury added that a short-term authorization permitting the sale of Iranian oil currently stranded at sea will expire in the coming days and “will not be renewed.”[30] The Trump administration has also sent warning letters to banks in Oman, the United Arab Emirates, Hong Kong, and the PRC, stating that financial institutions facilitating Iranian funds could face secondary sanctions and potential exclusion from the US financial system.[31]
Pakistan is reportedly pushing the United States and Iran to extend the ceasefire by 45 days.[32] US President Donald Trump told ABC News on April 14 that he is not considering extending the ceasefire.[33] The ceasefire is set to expire on April 22.
Iran is exploiting the current ceasefire to reorganize and regenerate its ballistic missile forces on the tactical level. Satellite imagery observed by CNN on April 14 showed that Iran attempted to remove debris in front of the entrances to the Southwest Tabriz Missile Base in Tabriz, East Azerbaijan Province, and the Khomein Missile Base in Khomein, Markazi Province.[34] An Israeli geospatial analyst assessed that the internal structures of the Khomein and Tabriz missile bases “appear to still be intact” and that missile stockpiles are likely still there.[35] The combined force struck the Khomein Missile Base on February 28 and the Tabriz missile base on March 3.[36] The combined force struck the entrances of multiple Iranian missile bases over the course of the conflict, likely to degrade Iran’s ability to access missiles and missile launchers.[37] Iran is exploiting the lack of combined force strikes to move and use the construction equipment (such as bulldozers) necessary to access the missile launchers at Khomein and Tabriz. Unspecified sources told CNN on April 14 that US intelligence officials assessed that roughly half of Iran’s missile launchers are still operational.[38]
Iran reportedly utilized an advanced reconnaissance satellite purchased from the People’s Republic of China (PRC) in 2024 to target US military assets and bases across the Middle East during the war.[43] Leaked Iranian military documents obtained by the Financial Times indicate that the IRGC Aerospace Force covertly purchased the Chinese Earth Eye TEE-01B reconnaissance satellite in 2024 for $36.6 million after its launch and transferred the satellite to the IRGC while in orbit.[44] The TEE-01B’s reported half-meter-per-pixel imagery resolution is comparable to Western models and enables the IRGC to identify aircraft, vehicles, and infrastructure changes, which likely supports Iranian battle damage assessments and targeting refinement.[45] The Financial Times reported that it obtained time-stamped coordinate lists, satellite imagery, and orbital analysis, which indicated that Iranian commanders tasked the satellite with monitoring key US military sites and captured images in March before and after drone and missile attacks on said locations.[46] China also granted the IRGC Aerospace Force access to Emposat’s commercial ground stations, a Beijing-based satellite control and data provider with a global network.[47] Empostat is reportedly closely linked to the People’s Liberation Army (PLA) Aerospace Force, including PLA personnel associated with key Empostat satellite launch command centers.[48] The combined force has repeatedly struck Iranian satellite ground stations during the 12-Day War and the current war in Iran, but by utilizing commercial ground stations outside of Iran, the IRGC prevented Israeli strikes.[49] The leaked data showed that the satellite captured imagery of Prince Sultan Air Base in Saudi Arabia from March 13 to 15.[50] This corresponded with Iranian ballistic missile attacks on Prince Sultan Air Base, which damaged five US KC-135 refueling tankers.[51] Other data showed that the satellite also conducted surveillance of the Muwaffaq Salti Air Base in Jordan and locations close to the US Fifth Fleet naval base in Manama, Bahrain, and Erbil airport, Iraq, contemporaneous with IRGC-claimed attacks on facilities in those areas.[52] The satellite also captured imagery of critical infrastructure that Iran struck in Gulf states, such as the Alba Aluminum facility in Bahrain, which Iran struck on March 29.[53] The Financial Times report on the IRGC’s utilization of Chinese intelligence assets for offensive capabilities follows a similar Washington Post report that Russia reportedly shared intelligence with Iran to support Iranian attacks against US forces in the Middle East in March.[54]
https://understandingwar.org/research/middle-east/iran-update-special-report-april-15-2026/