Five Britons have been detained by the Iranian navy while sailing a yacht from Bahrain to Dubai, the Foreign Office (FCO) has said.
The sailors were crewing a boat belonging to Sail Bahrain when they were stopped on 25 November.
In a statement, the FCO said it was possible the crew, who are still in Iran, may have “strayed inadvertently into Iranian waters”.
The five are understood to be safe and well and their families have been told.
FCO officials have had contact with Iran’s ministry of foreign affairs and the Iranian embassy in the UK.
It is not known where the sailors are being held nor which club they had come from, but the FCO did confirm they were on their way to a Dubai-Muscat race.
Foreign Secretary David Miliband said he hoped the issue would be resolved “soon”.
“FCO officials immediately contacted the Iranian authorities in London and in Tehran on the evening of 25 November, both to seek clarification and to try and resolve the matter swiftly.
“Our ambassador in Tehran has raised the issue with the Iranian foreign ministry and we have discussed the matter with the Iranian embassy in London,” he said.