Iran said Monday it was interrogating 15 detained British sailors and marines to determine whether they intentionally entered Iranian waters — an indication the country might be seeking a way out of the confrontation with Britain.

Britain denies its personnel had left Iraqi territory when they were captured and detained by Iran — a contention backed by Iraq's foreign minister, who called on Iran to release the group.

In comments read out by a newscaster, Iranian Deputy Foreign Minister Mehzi Mostafavi did not say what Iran plans to do with the British sailors, but he said they were being interrogated.

"It should become clear whether their entry (into Iran) was intentional or unintentional. After that is clarified, the necessary decision will be made," Mostafavi said.

Britain and the United States have said the sailors and marines were intercepted Friday just after they completed a search of a civilian vessel in the Iraqi part of the Shatt al-Arab waterway leading to the Persian Gulf, where the border with Iran has historically been disputed.

Separately, Iran's ambassador to Iraq, Hassan Kazemi Qomi, told The Associated Press in a telephone interview from Baghdad that there was no connection between the seizures of the 15 and any other issues between the West and Iran. He, like Mostafavi, denied any aim for a prisoner swap.

"They entered Iranian territorial waters and were arrested and are undergoing the process of investigation and interrogation. It has nothing to do with other issues," he said.

The United States holds at least five Iranians taken captive in Iraq, claiming they part of an Iranian Revolutionary Guard force that provides funds, weapons and training to Shiite militias in Iraq.

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The question of where exactly the 15 Britons were when detained has proved impossible to confirm independently, with Britain asserting they were in Iraqi waters but refusing to release precise geographical data and Iran asserting the opposite.

British Prime Minister Tony Blair's office sought to play down fears that the incident would deepen tensions with Iran, which threatened to charge the 15 with illegally entering its territory.

The seizure of the British service personnel has deepened troubles between Iran and the West, which is concerned about Iran's nuclear program and accused the country of interfering with the U.S.-led war in Iraq.

Blair's spokesman said he intended to treat the seizure as a distinct issue. "This is a matter that should be dealt with on its own merits," he said.

Iran rejected British requests to visit the group.

British Ambassador to Iran Geoffrey Adams held talks Monday with a senior Iranian Foreign Ministry official, who assured him the personnel are "fit and well" and being held inside Iran, Britain's Foreign Office said.

The U.N. Security Council agreed Saturday to tougher sanctions against Iran for its refusal to meet U.N. demands that it halt uranium enrichment. Many in the West fear the country's civilian nuclear research is a cover for a weapons program — a claim Iran denies.

The British government has few easy options for freeing its personnel, said Patrick Cronin, the director of studies at the London-based International Institute for Strategic Studies. He said that a rescue operation was out of the question, leaving Britain to seek some kind of negotiated settlement.

"Britain is in a very difficult situation, and this won't be settled easily," Cronin said. "They have to look at what is the least-worst option."

Iraq joined the European Union and the United States on Monday in backing Britain as Iraqi Foreign Minister Hoshyar Zebari told Iranian Foreign Minister Manouchehr Mottaki that the personnel were captured in Iraqi territorial waters and called for their release "legally and wisely."

Analysts said the seizure was likely linked to tensions between the West and Iran despite insistence from both countries that it would not affect wider diplomatic issues.

"It seems much more than coincidence that it happened right before the U.N. voted," said Alex Bigham, an Iran expert at Britain's Foreign Policy Center. "One could say, that yet again Iran has badly miscalculated and this is only going to further damage its relations with the international community."

In June 2004, six British marines and two sailors were captured by Iran and paraded blindfolded on Iranian television. They admitted they had entered Iranian waters illegally but were released unharmed after three days.

Scott Fallon, an ex-marine and one of the eight held in 2004, said his captors staged mock executions and accused him of espionage. "They just wanted to know our mission — why we were there, why we were in Iran," Fallon told British Broadcasting Corp. radio. "I suppose the same thing will be going on with these guys.

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