After marathon negotiations, the U.N. Security Council agreed late Thursday afternoon on a watered-down press statement expressing "grave concern" at Iran's capture of 15 British sailors and marines and calling for an early resolution of the problem, including their release.

Primarily because of Russian opposition, Britain failed to win council support for a stronger statement that would "deplore" Iran's detention of the Britons and call for their immediate release.

A press statement is the weakest action the council can take, but the statement must be approved by all 15 council members. A presidential statement, unlike a press statement, also needs consensus but is read at a formal Security Council meeting and becomes part of its official record.

Iran, meanwhile, tried to turn one of the captured sailors, a 26-year-old British mother, into a propaganda pawn, releasing what it claims is a letter from her in which she admits and apologizes for "wrongdoing."

Tehran also issued a veiled threat of trials if Britain does not admit the military personnel were in its territorial waters.

Iran's foreign minister had said Tehran would free Faye Turney, a young mother and the only woman among the 15 sailors and marines seized last week while searching a merchant vessel off the coast of Iraq but in what Iran claims were its territorial waters.

But Gen. Ali Reza Afshar, Iran's military chief, said that because of the "wrong behavior" by the British government, "the release of a female British soldier has been suspended," the semiofficial Iranian news agency Mehr reported.

Iranian negotiator Ali Larijani also told state television that British leaders "have miscalculated this issue" and if they follow through with threats, the case "may face a legal path" — presumably putting the Britons on trial.

Iranian state television broadcast a few seconds of video Thursday that it said was of the operation that seized the British sailors and marines.

In the five-second video, a helicopter is seen hovering above inflatable boats in choppy seas. Then, the Royal Navy sailors and marines appear seated in an Iranian vessel, presumably after their capture.

The video also displayed what appeared to be a handwritten letter from Turney, 26, to her family.

"I have written a letter to the Iranian people to apologize for us entering their waters," it said. The letter also asks Turney's parents in Britain to look after her 3-year-old daughter, Molly, and her husband, Adam.

Analysts immediately doubted the validity of the letter, saying the wording was not likely to have been thought up by the 26-year-old sailor.

Click here to read the full txt of the letter.

The video showed Turney in a head scarf and her uniform eating with other sailors and marines. Later, wearing a white tunic and black head scarf, she sat in a room before floral curtains and smoked a cigarette.

Turney was the only detainee shown speaking, saying she had been in the navy for nine years.

"Obviously we trespassed into their waters," Turney said at one point. "They were very friendly and very hospitable, very thoughtful, nice people. They explained to us why we've been arrested. There was no harm, no aggression."

Britain angrily denounced the video as unacceptable and froze most dealings with Iran.

"Nobody should be put in that position. It is an impossible position to be put in," said Blair's spokesman, who spoke on condition of anonymity in keeping with government policy. "It is wrong. It is wrong in terms of the usual conventions that cover this. It is wrong in terms of basic humanity."

The third Geneva Convention bans subjecting prisoners of war to intimidation, insults or "public curiosity." Because there is no armed conflict between Iran and Britain, the captives would not technically be classified as prisoners of war.

Britain's ambassador to Tehran lodged an official complaint, the Foreign Office said.

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Britain insists that the vessel and its naval personnel were in Iraqi waters, and that satellite positions prove it, but Iran says the Britons were seized in its territorial waters, and claims it has satellite proof as well.

Iran's foreign minister, Manouchehr Mottaki, told The Associated Press on the sidelines of an Arab summit in Saudi Arabia on Wednesday that Britain must admit that its sailors entered Iranian waters for the standoff to be resolved.

But Britain's Foreign Office insisted on Thursday that the crew was seized in an Iraqi-controlled area and no admission would be forthcoming.

During initial closed-door discussions in the council on Thursday afternoon, diplomats said, several council members had problems with the British draft, including Russia and Indonesia.

Russia, which has strong commercial links with Tehran, raised serious objections to the thrust of the British statement — deploring Iran's actions, stating that the incident took place in Iraqi waters and demanding the immediate release of the Britons, the diplomats said.

Russia's U.N. Ambassador Vitaly Churkin, who emerged briefly, said only that he had made "constructive suggestions" and hoped members could agree on a statement.

In addition to taking the issue to the Security Council, Britain enlisted international help to free the captives.

U.N. Secretary-General Ban Ki-moon discussed their fate with Mottaki over breakfast Thursday on the sidelines of the Arab summit that both were attending. Ban called for an early resolution of the problem, the U.N. spokesman's office said.

European Union foreign policy chief Javier Solana urged Iran to free the captives, saying the standoff is blocking efforts to improve relations. In Paris, the Foreign Ministry summoned the Iranian ambassador to express concern and urge their release.

In Iraq, the Iranian consul in Basra charged that British soldiers on Thursday had surrounded his office and fired shots into the air. The Ministry of Defense in London said the shooting was an exchange of gunfire after British troops on a foot patrol near the Iranian consulate were ambushed.

But Iranian Consul-General Mohammed Ridha Nasir Baghban said British forces had engaged in a "provocative act" that "could worsen the situation of the British sailors."

"British forces should rely on wisdom and not react because of the British forces' detention. This reflects negatively on bilateral relations," Baghban told AP.

The Associated Press contributed to this report.