Europen Union foreign ministers have called for the immediate and unconditional release of 15 British naval personnel seized by Iran in the Persian Gulf a week ago.
Britain has denied claims by Iran that the crew had been in Iranian territorial waters when they were arrested.
A joint statement issued by the ministers at a meeting in Germany said that Iran's seizure the navy personnel was a breach of international law and threatened to take action if they were not released soon.
The statement also echoed UN Security Council call for Iran to inform Britain of the whereabouts of the 14 men and one woman and to grant consular access.
Earlier, British Prime Minister Tony Blair again criticised Iran for filming and broadcasting an apparent apology by a second member of the navy crew.
In the footage broadcast on Iranian television, the crewman, named as Nathan Thomas Summers, apologised for what he described as 'trespassing' in Iranian waters.
On Wednesday, Faye Turney, the only woman among the 15 sailors and marines captured in the Persian Gulf last week, was shown on television making similar comments.
Mr Blair said no one would be fooled by Tehran's ploy of parading the captured troops.
The British Foreign Office has described the latest video as 'disgraceful exploitation'.
It came as Iranian President Mahmoud Ahmadinejad called on Britain to apologise to Tehran.
Diplomatic efforts by Britain
The Britain government has been trying to secure the release of the 15 navy personnel through diplomacy at the UN and the EU.
The UNSC has agreed a statement voicing 'grave concern' at Iran's capture of the 15 British navy personnel.
In a statement today, Mr Blair said that if Iran continued in this way it would face international isolation.
He said there was no question about the unlawful nature of their capture and that it had to be managed in a measured and calm way.
Meanwhile, a letter last night from Iran's foreign ministry to the UK ambassador in Tehran offering a forum in which to discuss how to avoid such incidents in the future has been dismissed by Foreign Secretary Margaret Beckett as containing nothing new.
