A tanker reported an external explosion roughly 60 nautical miles off the Omani capital Muscat on Tuesday afternoon, according to the UK Maritime Trade Operations (UKMTO).

The explosion struck the aft section of the vessel — towards its rear — close to the waterline, the agency said. The vessel and its crew are safe, though the tanker reported that “some bunker fuel” was discharged into the sea. Authorities are investigating, UKMTO said, advising ships in the area to transit with caution.

The maritime news outlet gCaptain identified the vessel as the Marshall Islands-flagged crude tanker Olympic Life. No party has claimed responsibility for the blast, and its cause remains under investigation.

The incident comes days after the United States struck two Iranian boats laying mines in the Strait of Hormuz and a naval base near Bandar Abbas, after which Iran’s Revolutionary Guard vowed revenge and shot down a US MQ-9 drone over the strait. The waters off Oman lead into the Strait of Hormuz, the chokepoint for about a fifth of the world’s seaborne oil and a route on which Sri Lanka depends for its fuel imports.

It is the latest in a series of vessel incidents off Oman during the conflict, after an Iranian gunboat opened fire on a container ship in the same waters in April — even as the first tankers began exiting Hormuz earlier this week.