British armed forces supported the US seizure of a Russian-flagged oil tanker in the North Atlantic on Wednesday, the Ministry of Defence has said.
The Marinera, a Venezuelan-linked tanker previously known as the Bella 1,
was stopped by the US Coast Guard, as it travelled northwards through waters between Iceland and Scotland.
The MoD said the US asked the UK for assistance, and RAF surveillance aircraft and a Royal Navy support ship, the RFA Tideforce, took part in the operation.
Defence Secretary John Healey said the action was "in full compliance with international law", adding the UK "will not stand by as malign activity increases on the high seas".
In a statement to MPs on Tuesday explaining why the UK joined the operation, Healey said the government was "stepping up activity against shadow vessels".