The EU called on Iran to release the 15 British sailors and marines it is holding in its custody "immediately" and sent a warning it would "decide on appropriate measures" if Tehran did not comply.

The statement did not elaborate on what such measures would be.

The EU told Tehran to tell the British government where the prisoners are being held to allow British diplomats access to them.

In a statement released after EU foreign ministers met in Bremen, Germany, on Friday, they said "all evidence clearly indicates that at the time of the seizure, the British naval personnel were on a routine patrolling mission in Iraqi waters in accordance with United Nations Security Council resolution 1723."

"The seizure," the statement went on to say, "represents a clear breach of international law."

The EU statement is stronger than that of the UN Security Council which on Thursday expressed "grave concern" at the naval personnel's detention but declined to back Britain with a call for their immediate release.

"A big mistake"

Britain froze official contacts on Wednesday with Iran as the dispute over the detained sailors intensified, with Prime Minister Tony Blair vowing to "ratchet up" pressure on Tehran.

EU foreign policy chief Javier Solana called the Iranian action "a big mistake" and called for the release of the sailors, who were captured on March 23.

"I don't understand. It's a big mistake. They should release the soldiers immediately," he said as he entered the meeting. "I have total confidence that the British boat was in Iraqi waters," he added, alluding to Iran's claims that the boat had entered its waters.

However, there was opposition in the EU to freezing business with Tehran, which diplomats said Britain had initially sought.

French Foreign Minister Philippe Douste-Blazy said Friday that all steps must be taken to avoid an escalation between Britain and Iran.

"We must avert a course towards confrontation, any escalation," said Douste-Blazy in an interview to RTL radio. "The Iranian authorities must simply return to dialog."

British sailor apologizes on Iranian TV

Britain insists the 14 men and one woman were in Iraqi waters carrying out routine anti-smuggling operations when they were seized.

Meanwhile Iranian television broadcast footage of three of captured British sailors and marines on Friday and said one had confessed to entering Iranian waters illegally and had apologized to the Iranian people.

"We trespassed without permission. Since we have been arrested our treatment has been friendly. We have not been harmed at all," one of them, whose name was read out as Nathan Thomas Summers, said on state television. "I would like to apologize for entering your waters without any permission ... I deeply apologize," he said. "They have looked after us really well."

The informal EU meeting in Bremen was a chance for the ministers to discuss the top issues of the day without being constrained by the need to reach agreed conclusions.

This one was scheduled to focus on Kosovo and the Middle East, but "with the current situation with the British soldiers there is a particular case," an EU diplomat said.

Call for UN inquiry

The initial British draft for the UN, circulated Wednesday, had asked the council to "deplore the continuing detention by the government of Iran of 15 UK naval personnel" and to back "calls for (their) immediate release."

But Britain failed to win council support for the strong statement, call for the sailors' immediate release, and state that they were seized in Iraqi waters, because of opposition from some council members, primarily Russia.

Russia's foreign ministry on Friday said the United Nations should conduct an independent probe of circumstances surrounding the capture of the British sailors by Iran. The ministry made the call in a statement released after talks between British Ambassador Anthony Brenton and Russian Deputy Foreign Minister Alexander Yakovenko.

"Taking into consideration the fact that the British side insists the service personnel were fulfilling the mandate of the UN Security Council, we consider that the UN Secretariat should prepare an independent report regarding this particular incident," the ministry said in a statement.