Two crew were wounded when an "unknown projectile" hit a tanker Monday in the Strait of Hormuz, where vessels have been under fire during the Middle East war, a maritime agency said.
Tehran is seeking to maintain a stranglehold on the vital waterway in its war with the United States, while Washington has kept up a counterblockade of Iranian ports.
"Military authorities have informed UKMTO that a tanker conducting an inbound transit was struck by an unknown projectile," said the United Kingdom Maritime Trade Operations (UKMTO).
"Two crew have sustained minor injuries and the vessel is reported to be continuing to its next port of call under its own power," it added.
British security firm Vanguard Tech said UK-flagged tanker La Stephanie was hit by a drone while sailing towards the Gulf, also reporting minor injuries to two crew members.