TEHRAN - Iran displayed three detained British naval personnel on television on Friday and released a letter from one saying she was being held because of "oppressive" British and US behaviour in Iraq.
Prime Minister Tony Blair said the footage of three of the 15 British captives heightened people's disgust at the treatment of the sailors and marines and risked isolating Tehran further -- but he urged calm and patience over the crisis.
"I am writing to you as a British service person who has been sent to Iraq, sacrificed due to the intervening policies of the Bush and Blair governments," said the third letter from sailor Faye Turney, released by Iran's embassy in London.
London has been pushing for international condemnation but failed to get the UN Security Council to pass a strongly worded draft statement. Instead, it expressed "grave concern."
Russia, which had blocked moves for a stronger position, said it wanted the UN Secretariat to deal with the dispute.
EU foreign ministers voiced solidarity with Britain at a summit in Germany but stopped short of suspending normal business with Tehran over the week-old row as London has done.
White House spokeswoman Dana Perino said: "Tony Blair has made his comments and we strongly stand behind him."
Asked if she believed the crisis was closer to confrontation and armed conflict, she said "There's no indication of that. No, I believe that everyone believes it can be solved diplomatically."
Iran seized the sailors and marines in the northern Gulf last Friday when they were on a UN mission searching for smugglers in Iraqi waters. Tehran says they strayed into Iranian waters but Britain insists they were well in Iraqi territory.
British forces have been deployed in southern Iraq since joining the US-led invasion of the country in 2003. Britain and the United States accuse Iran of allowing sophisticated weapons used to target their forces to be brought into Iraq.
The crisis, at a time of heightened Middle East tensions over Iran's nuclear ambitions, has helped push oil prices to six-month highs over concerns an escalation might curb crucial oil exports from the region.
The video showed two men in khaki uniforms and a woman in blue fatigues and a headscarf talking calmly and smiling in a room with a floral wallpaper background.
"We trespassed without permission," said the sailor, who gave his name as Nathan Thomas Summers and said they were being treated well. "I would like to apologise for entering your waters without any permission ... I deeply apologise."
Blair said the only possible outcome from the standoff was the release of the British personnel and that London would consult its allies over the weekend.
"I really don't know why the Iranian regime keeps doing this. All it does is enhance people's disgust at captured personnel being paraded and manipulated in this way," he said.
"What the Iranians have to realise is that if they continue in this way they will face increasing isolation."
The video release came as Britain said it was considering a note from Tehran that appeared to resemble a statement used to resolve a similar standoff in 2004 when Iran seized eight British servicemen and held them for three days.
However Foreign Secretary Margaret Beckett said after the video was shown that there was nothing in the note from Iran to suggest Tehran was looking for a way out.
The letter said Iran respected the rules and principles of international law concerning the territorial integrity of states and that Britain must accept its responsibility for the consequences of any border violation.
The letter did not appear to demand an apology from Britain as several Iranian officials had previously called for.
In London, Iran's embassy said both governments were working together closely to find a mutually acceptable solution and that it could be settled bilaterally.
Analysts said efforts to resolve the standoff were complicated by Iran's political structure.
"The Iranian Foreign Ministry is not in charge here," said Mark Fitzpatrick, senior fellow for non-proliferation at the International Institute for Strategic Studies.
"They're having to work out a face-saving diplomatic solution, but I don't think the Revolutionary Guards want a diplomatic solution. So it's going to be hard to choreograph something when you have internal friction."
The hardline Guards are the ideological wing of Iran's armed forces with a separate command structure.