An oil tanker struck a mine and caught fire in the Strait of Hormuz after entering a prohibited area, Iran’s army said on Wednesday.

Separately, the UK Maritime Trade Operations agency said it had received a report of an incident involving a tanker in the Strait of Hormuz. It said the condition of the crew, the extent of any damage and the environmental impact were not yet known. It was not immediately clear whether the report referred to the same vessel.

Iran has restricted traffic through the strategic waterway since the war in the Middle East began in late February, and has been targeting vessels that pass through without its authorization.

Iran’s Islamic Revolutionary Guard Corps said three oil tankers had caught fire in the strait recently. In one incident, a Liberia-flagged tanker was hit by a projectile, injuring several people, including an Indian national who was taken ashore safely.

Tehran has reported a number of ships catching fire in the strait, often blaming mines, despite recent US claims that all mines in the area had been cleared.

The US has imposed a naval blockade on Iranian ports and has been helping tankers through the strait, which carries around a fifth of the world’s oil.

US Central Command, which oversees American military operations in the region, has been escorting ships and helping Gulf countries export oil through Hormuz. It says around 1.5 billion barrels have passed through since the summer.