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.
The Tasnim news agency quoted the Ports and Maritime Organisation of Iran as saying: "We received some reports on the British oil tanker, Stena Impero, causing problems.
"We asked the military forces to guide this tanker towards Bandar Abbas port to have the required investigations carried out."
This latest development comes amid heightened tensions between the UK and Iran.
Hakuna mambo ya 'false flag' hapa, ni tit-for-tat.
Iran knows how thirsty the hypocritical west is where oil is involved. It is forcing the Brits to come out in the open about its habit of collaborating with the USA to manipulate Muddle East politics. If it causes enough trouble in the Strait, there will be negotiations.
Israel and uk needs the us to be at war with Iran to keep it onto perpetual war mongering acts , and riddle the USA corporation into bankruptcy while feeding the military industrial complex.
The Zionist tried pushing it so hard using false flags with the help of False media but the MAGA patriots seem to be tired of loosing their sons in war fighting other countries interests... Trump knows, he starts war, he looses the election.