Iran’s Islamic Revolutionary Guard Corps Navy announced Saturday that a second supertanker struck a naval mine and caught fire in the Strait of Hormuz, the second such incident it has claimed in about 24 hours. The IRGC says the ship was carrying more than two million barrels of crude, had switched off its positioning and radar systems, and was trying to cross by a route Iran has not authorized. It claims a powerful explosion tore through the engine room and left the tanker stopped, and it accused the U.S. military of misleading the vessel into the passage. The IRGC has not named the ship or said anything about its crew, casualties, or possible oil spill damage, and there has been no independent confirmation of the account.

The claim lands as Iran insists the strait is closed and warns that ships ignoring its rules will face consequences, while the United States and its regional allies reject those restrictions and stand by freedom of navigation. Earlier this week, the IRGC said a container ship carrying more than 2,500 containers sank after hitting a mine south of the strait, and a British navy-affiliated maritime agency reported that a 50,000-tonne container vessel hit a mine while passing through. U.S. Central Command also pushed back on the IRGC commander’s claim that Iranian forces control the waterway. Mines are a real hazard here, since U.S. officials said in August that more than 100 suspected mines had been identified and dealt with after Iran closed the route earlier this year. Until the ships are named and outside observers confirm what happened, the big questions remain who laid the mines, which route the tankers took, and how much more danger lurks in one of the world’s most important oil passages.