A British-flagged oil tanker has been seized in the Gulf by the Iranian Revolutionary Guard, Iran media say.
The owners of the Stena Impero, which was bound for Saudi Arabia, say they have been unable to contact the vessel and it is “heading north towards Iran”.
The company says there are 23 personnel on board and it was approached by “unidentified small crafts and a helicopter” in the Strait of Hormuz.
The Foreign Office is “urgently” looking into the reports.
The government’s emergency committee, Cobra, is meeting in Whitehall to discuss the incident.
This latest development comes amid heightened tensions between the UK and Iran.
Stena Bulk, the vessel owner, and ship manager Northern Marine Management confirmed the UK-registered Stena Impero was approached at around 16:00 BST on Friday while it was in international waters.
A statement said: “We are presently unable to contact the vessel which is now heading north towards Iran.
“There have been no reported injuries and their safety is of primary concern to both owners and managers.”