An Iraq-focused journalist said that Iraqi Security Forces arrested Kataib Hezbollah (KH) and Harakat Hezbollah al Nujaba fighters on December 14 in connection to the December 8 rocket attack on the US Embassy in Baghdad.[48] A senior Iraqi security official told the journalist that the militias ”crossed lines” and that the situation is ”serious.”[49] CTP-ISW previously reported that the ISF arrested militia members on December 14, but the Iraqi government did not specify to which militia the fighters belonged.[50] The Iraqi central government has previously arrested KH and KH-linked fighters. The Iraqi judicial system released the fighters on both occasions after armed Iranian-backed fighters stormed Baghdad's Green Zone. Iraq's Counter Terrorism Service (CTS) raided a Kataib Hezbollah compound in June 2020, arresting 14 KH fighters.[51] Then-Prime Minister Mustafa al Kadhimi’s government released the KH fighters after KH fighters—led by Iranian proxy and KH leader Abu Fadak al Muhammadawi—stormed the Green Zone.[52] Kadhimi’s government also arrested the commander of KH-affiliated Liwa al Tafuf in May 2021, but released the commander after 12 days.[53] The commander's arrest caused an armed standoff between PMF fighters and ISF units in the Green Zone.[54]
https://www.understandingwar.org/backgrounder/iran-update-december-16-2023
The Houthi anti-shipping attack campaign continues to achieve one of its desired effects of disrupting maritime traffic headed to Israel. Hong Kong-based shipping company Orient Overseas Container Line (OOCL) announced on December 17 that it would immediately stop shipping goods to and from Israel.[77] The company cited “operational issues” for the policy.[78] OOCL is the first global shipping company that CTP-ISW has observed to specifically halt operations to Israel since the Houthis began their campaign against international shipping around the Bab al Mandeb in November.[79] Global shipping giants, such as Mediterranean Shipping Company, CMA CGM, Maersk, and Hapag-Lloyd, previously announced that they would pause operations around the Red Sea but did not specify how it would affect their services to Israel.[80] Houthi spokesperson Mohammed Abdulsalam commended OOCL’s decision to stop sending ships to Israeli ports and falsely asserted that the Houthis are only attacking ships linked to Israel on December 17.[81] Several of the ships that the Houthis have attacked in recent days were en route to destinations outside of Israel, such as Saudi Arabia.
full report: https://www.understandingwar.org/backgrounder/iran-update-december-17-2023
The Iranian connection is well known. This is from 2021:
Iran has provided the Houthis with weapons and technology for anti-tank guided missiles; sea mines; UAVs, such as the Qasef family; 122-millimeter Katyusha rockets; Misagh-2 man-portable air defense systems (MANPADS); RDX high explosives; ballistic and cruise missiles; and UMVs. One specific example is the Houthi use of Borkan-2H mobile, short-range ballistic missiles, which they have used to strike Riyadh and other targets in Saudi Arabia. A UN panel of experts concluded that the missiles were “a derived lighter version” of Iran's Qiam-1 missile and that Iran provided key missile parts to the Houthis. Iranian components were also integrated into Yemeni SA-2 surface-to-air missiles to construct the Qaher series of surface-to-surface missiles. The Houthis have also developed a modified version of the Iranian Quds-1 and Quds-2 cruise missiles, with Iranian assistance.
https://www.csis.org/analysis/iranian-and-houthi-war-against-saudi-arabia