A commercial cargo ship navigating the Arabian Gulf was struck by an unidentified projectile, triggering a "large explosion," according to the United Kingdom Maritime Trade Operations (UKMTO).

The maritime strike took place approximately 65 nautical kilometers (40 miles) southeast of Umm Qasr, Iraq. At this time, the UKMTO noted that it is unaware of any environmental damage resulting from the blast.

Initially Iraqi media reported the blast was due to "mechanical failure" - but soon after other regional media said it was the result of being hit by a "massive projectile".

"A cargo ship was hit by a massive projectile explosion off the coast of Umm Qasr in Iraq, according to Al Hadath, a Saudi-owned channel.

According to another maritime industry source:

Most of the attacks on commercial shipping in the Gulf region since the war in Iran started have been in and around the Strait of Hormuz, the Gulf of Oman, extending as far west as Bahrain and Qatar.

Only one other attack reported off Iraq was on the Greek-owned chemical/product tanker Zefyros and the US-owned Safesea Vishnu on 12 March which left one seafarer dead.

There have also been incidents off Kuwait with Suezmax tanker Sonangol Namibe  anchored 30nm southeast of Mubarak Al Kabeer was hit with a large explosion on 5 March. Kuwait’s Shuwaikh and Mubarak Al Kabeer Port were struck by drones and missiles on 27 March.

Unverified video is already circulating of what's said to be a Panama-flagged container ship:

Some areas in the vicinity have reportedly been subject to mine-laying by Iran's IRGC forces, making these waters already highly dangerous.

All of this has taken place as the US-Iran extended ceasefire is potentially breaking down Monday, following a weekend of limited tit-for-tat strikes between each warring side. Iran launched a pair of ballistic missile on a US base in Kuwait, and the US has struck radar and missile sites in Iran.