12 p.m. TEHRAN, Iran -- One of the 15 British service members held captive in Iran appeared Friday on state television and said he apologized ''deeply'' for entering Iranian waters, and the country released a third letter supposedly from the one woman in the crew saying she has been ''sacrificed'' by Britain.

British Prime Minister Tony Blair, whose government has insisted that its navy personnel were captured in Iraqi waters, immediately condemned Iran's treatment of the captives, saying it ''doesn't fool anyone.''

In the video Friday, Royal Marine rifleman Nathan Thomas Summers was shown sitting with another male serviceman and the female British sailor Faye Turney against a pink floral curtain. Both men wore camouflage fatigues with a label saying ''Royal Navy'' on their chests and a small British flag stitched to their left sleeves. Turney wore a blue jumpsuit and a black headscarf.

''We trespassed without permission,'' Summers said, adding he knew that Iran had seized British military personnel who strayed into their waters three years ago.

''This happened back in 2004 and our government said that it wouldn't happen again,'' Summers said. ''And, again, I deeply apologize for entering your waters.''

It was not known whether the marine spoke under pressure from his captors, but Summers said in the broadcast ''our treatment has been very friendly.''

Britain criticized the broadcast and Iran's treatment of the captives.

''I really don't know why the Iranian regime keep doing this. I mean all it does is enhance people's sense of disgust. Captured personnel being paraded and manipulated in this way doesn't fool anyone,'' Blair said. ''What the Iranians have to realize is that if they continue in this way, they will face increasing isolation.''

Iran earlier broadcast a video showing Turney saying her team had ''trespassed'' in Iranian waters, and on Friday released a third letter from her.

The first two letters attributed to Turney said she was sorry the crew strayed into Iranian waters and asked if it wasn't time for Britain to withdraw its troops from Iraq. The first letter was wooden; the second and third had language that was even more stilted.

''I am writing to you as a British serviceperson who has been sent to Iraq, sacrificed due to the intervening policies of the Bush and Blair governments,'' the letter Friday said.

British Foreign Secretary Margaret Beckett, who also denounced Friday's video as ''appalling,'' said a letter from Iran on the detention of the 15 sailors and marines had done nothing to bring the standoff to a close.

''There is nothing in the letter to suggest that the Iranians are looking for a way out,'' Beckett told the British Broadcasting Corp.

The letter stopped short of asking for a formal apology but instead asked for Britain to acknowledge its sailors had trespassed into Iranian waters and confirm that it would not happen again. The standoff has added to tensions over Iran's nuclear ambitions and over allegations that Iran is arming Shiite Muslim militias in Iraq.

The European Union on Friday warned of undefined ''appropriate measures'' against Iran if the British personnel remain in captivity.

The sailors, part of a U.N.-mandated force patrolling the Persian Gulf, were seized off the Iraqi coast while searching merchant ships for evidence of smuggling. Britain insists the sailors were seized in Iraqi waters and has said no admission of error would be made.

The TV showed pictures of the light British naval boats at the time of the sailors' seizure. The helicopter flying in the background was British, the Al-Alam newscaster said.

Britain has frozen most bilateral contacts and referred the issue to the U.N. Security Council, which expressed ''grave concern'' over Iran's seizure of the military personnel. Russia, which resisted a stronger Security Council statement, called Friday for an independent United Nations investigation.

Iran said Friday the Security Council had no place in what it called a purely bilateral dispute: ''The British Government's attempt to engage third parties, including the Security Council, with this case is not helpful.''

The Iranian statement, released by its mission at the United Nations and in London, said the British and Iranian governments ''have been closely examining and discussing the case in order to settle it in a mutually acceptable manner.''

''Manifestly, the case entails technical, security and legal aspects that require sufficient time to address,'' the mission said, without elaborating.

The office of the Turkish prime minister - who is trying to mediate the dispute - said Iranian President Mahmoud Ahmadinejad had indicated his government is willing to reconsider freeing Turney, who is married and has a young daughter.

Iran, which faced new Security Council sanctions just last week over its refusal to abandon uranium enrichment in its disputed nuclear program, has found few open defenders in the crisis.

Iran first broadcast the footage of the captives, both Wednesday's and Friday's video, on its Arabic-language TV channel, Al-Alam, rather than on its main Farsi channels. The decision, which was not explained, appeared to be an attempt to seek support from Arabs in Iraq and the Gulf states, where many resent Britain's military deployment in Iraq and its historical role as a colonial power in the region.

Iraq has taken Britain's side, reiterating Friday that the navy personnel were captured in its territorial waters. Iraqi Foreign Minister Hoshyar Zebari also said his government was in contact with Iran to ''ensure the wise handling of the case.''

The European Union vowed solidarity with Britain, but some diplomats also warned against avoid unnecessary escalation.

''We must put very strong pressure on the Iranians,'' French Foreign Minister Philippe Douste-Blazy said in a radio interview in Paris. ''I think we must avoid confrontation and escalation.''

Crude oil prices kept rising Friday as a jittery market worried that oil exports could be affected by the British-Iranian crisis.

After settling at a six-month high a day earlier, light, oil prices edged higher by midday Friday. Light, sweet crude futures for May delivery rose 15 cents to $66.18 a barrel by midday on the New York Mercantile Exchange in volatile trading.

Trading settled Thursday at $66.03 a barrel on the New York Mercantile Exchange - the highest settlement price since Sept. 8, 2006, when crude finished at $66.25.