TEHRAN, Iran — The largest warship in the Iranian navy caught fire and later sank Wednesday in the Gulf of Oman under unclear circumstances, the latest calamity to strike one of the country’s vessels in recent years amid tensions with the West.

The blaze began around 2:25 a.m. and firefighters tried to contain it, the Fars news agency reported, but their efforts failed to save the 679-foot Kharg, which was used to resupply other ships in the fleet at sea and conduct training exercises. State media reported 400 sailors and trainee cadets on board fled the vessel, with 33 suffering injuries.

The ship sank near the Iranian port of Jask, some 790 miles southeast of Tehran on the Gulf of Oman. Satellites from the U.S. National Oceanic and Atmospheric Administration that track fires from space detected a blaze near Jask that started just before the time of the fire reported by Fars.

Iranian officials offered no cause for the fire, though they said an investigation had begun.

The fire aboard the warship follows a series of mysterious explosions that began in 2019 targeting commercial ships in the Gulf of Oman. The U.S. Navy accused Iran of targeting the ships with limpet mines, timed explosives typically attached by divers to a vessel’s hull.

Iran denied that, though U.S. Navy footage showed Revolutionary Guard members removing one unexploded limpet mine from a ship.

The attacks came amid heightened tensions between the U.S. and Iran after then-President Donald Trump unilaterally withdrew America from Tehran’s nuclear deal with world powers.