TEHRAN, Iran -- A British marine captured by Iranians a week ago was shown on state television yesterday apologizing for trespassing on Iranian territorial waters.

Royal Marine Rifleman Nathan Thomas Summers, seated with a female fellow captive, Leading Seaman Faye Turney, and another detainee, looked healthy and relaxed as he spoke.

"We illegally trespassed on Iran's territorial waters and were arrested by the Iranian border guards," said Rifleman Summers, seated before a pink floral curtain. "I would like to deeply apologize to the Iranian people for the issue."

The footage, along with a letter allegedly written by Seaman Turney criticizing British foreign policy, drew swift condemnation by British authorities as violations of international standards for treatment of the 15 captured sailors and Marines, as the tense standoff between Tehran and London entered a second week.

"I really don't know why the Iranian regime keeps doing this. All it does is enhance people's disgust at the captured personnel being paraded and manipulated in this way. It doesn't fool anyone," British Prime Minister Tony Blair said. He said Britain will continue its work to try to "isolate" Iran.

The European Union, in a meeting yesterday of EU foreign ministers in Bremen, Germany, demanded that Iran free the soldiers. Calling the crisis "a big mistake," EU foreign policy director Javier Solana said the "British soldiers should be released immediately and without preconditions."

German Foreign Minister Frank-Walter Steinmeier told reporters: "It is clear that a message of solidarity must be sent from here."

British officials insist that the 15 service personnel were on a routine inspection mission in the territorial waters of Iraq, where Americans and Britons assist the Baghdad government under a United Nations mandate. They have demanded their immediate release and obtained a U.N. statement Thursday calling for an end to the crisis.

Iran alleges that the 14 men and one woman illegally entered Iranian territorial waters. Both sides have released maps and GPS coordinates that they say bolster their cases.

Iranian officials have said that before they grant the sailors access to British diplomats in Tehran or consider releasing them, they want Britain to apologize and to vow never to cross into Iranian territorial waters again. London has refused.

Officials from Turkey, France, Iraq, Japan, Australia and the United Nations stepped in to contain the escalating diplomatic confrontation, which has sent world oil prices to six-month highs.

Iranian officials first announced that they would release Seaman Turney, the female captive, as a gesture of goodwill, but then reneged because they said they disapproved of the British tone. Yesterday, the representative of Supreme Leader Ali Khamenei in the security forces called again for Seaman Turney's release.

"In order to show Iran's special respect for women to the world and the implementation of Iran's policy of detente, and in view of her admission, the female sailor had better be released," mid-ranking cleric Mohammad Ali Rahmani told the Mehr news agency.

He said Iranian authorities should follow the same example as in 1979, when Ayatollah Ruhollah Khomeini ordered the release of female American diplomats in Tehran. "The release of this female sailor would break a fake and heavy ambience fabricated by the Westerners against Iran," he said. "Then the Islamic Republic can deal with the male sailors in accordance with international regulations." But other Iranian hard-liners apparently steering the matter showed no signs of backing down. Prayer leaders throughout the country yesterday demanded that the British sailors and Marines stand trial on charges of violating Iran's territorial waters.

"We are neither looking for a conflict nor tension in the region," Tehran Friday prayer leader Ahmad Khatami told worshippers yesterday. "But we will not allow any country to violate our territory --and especially not Britain, which has no positive record in Iranian history."

Iranian officials also have demanded that the United Nations and the European Union not get involved in the issue.

"The Britons have to admit that their sailors have strayed into Iran's waters, and they must give us guarantees to not repeat it," Foreign Minister Manouchehr Mottaki said in a conversation with his Japanese counterpart, according to the state news agency. "Instead of adopting a proper diplomatic approach and taking positive steps, Britain has politicized the issue."

Rifleman Summers appeared seated in his uniform. "Since we were arrested on March 23, 2007, everything has been OK, and I am quite satisfied with the current conditions," he said in the video. "Over the past days, Iranian forces have shown us a very friendly and good behavior, and no ill treatment has been observed."

In Seaman Turney's purported letter, she asked members of Britain's Parliament to consider pulling U.K. troops out of Iraq. "I believe that for our countries to move forward, we need to start withdrawing our forces from Iraq and leave the people of Iraq to start rebuilding their lives," she allegedly wrote.