The UN’s International Maritime Organization (IMO) temporarily halted its evacuation effort for ships and crews stranded by the closure of the Strait of Hormuz after an attack on a vessel in the Gulf of Oman.

IMO Secretary-General Arsenio Dominguez said he was informed a vessel passed through the Strait of Hormuz and was then attacked in the Gulf of Oman, and he decided to pause the operation “to temporarily pause its implementation” while authorities reconfirm that safety guarantees remain in place for ships on the IMO evacuation list and for vessels in the region.

A UK maritime tracking operation reported a cargo vessel off Oman was hit by an “unknown projectile,” causing damage to its bridge, and no casualties were reported; the ship was not identified.

Iran also warned that passage outside routes approved by the Islamic Republic would not be guaranteed safe, and said such vessels “will be dealt with accordingly,” adding pressure on the UN-backed route plan amid the still-contested US-Iran arrangement around reopening the corridor.

The IMO’s evacuation plan, announced earlier in the week, aimed to help about 11,000 seafarers escape via a UN-recommended framework that began rolling out at the start of the week, with some ships already transiting before the attack prompted the pause.