Iran's military said today British naval personnel seized in the Gulf confessed to entering its waters illegally, but Britain maintained they were detained inside Iraqi territory.
Iranian forces captured 15 British sailors and marines on Friday at the mouth of the Shatt al-Arab waterway, which marks the southern stretch of Iraq's border with Iran, sparking a diplomatic crisis at a time of increased tension over Tehran's nuclear standoff with the United States and other major powers.
The semi-official Fars news agency said they had been transferred to Tehran to explain their "aggressive action", but this could not be immediately confirmed.
Fars also said the Britons included some women.
"These people are under investigation and have confessed they have violated the waters of the Islamic Republic of Iran," the ISNA news agency quoted a military official as saying.
The official, Deputy Commander Alireza Afshar, told state radio the Britons were in good health. "The investigation is going on and they are healthy and there is no problem."
He said they were detained on Friday by naval units of the Revolutionary Guards, the ideologically driven wing of the armed forces which has a separate command structure from the regular military. Britain has not released the identities of the personnel.
"We still maintain they were in Iraqi waters when they were picked up," a British diplomat in Tehran said, adding he had no information they had been moved to the capital. Another British envoy earlier cited reports suggesting they had been taken to a military base in southwestern Iran after their capture.
Britain said two boatloads of Royal Navy sailors and marines had searched a merchant vessel on a UN approved mission in Iraqi waters when Iranian gunboats encircled and captured them. Iran's Foreign Ministry condemned what it called the illegal entry into Iranian waters as a "suspicious act", the official IRNA news agency said.
The incident sent oil prices up more than one per cent to a three-month high on Friday. It took place a day after Iran launched a week of naval war games along its coast, including the Gulf's northern reaches which give access to the oil output of Iraq, Iran and Kuwait.
It also came ahead of today's expected UN Security Council vote to impose new arms and financial sanctions on Iran over its refusal to suspend uranium enrichment programme, which the West suspects is designed to make atom bombs.
Tehran denies the charge, saying it is only aimed at generating power in the world's fourth largest oil exporter.
Meanwhile, the European Union president Germany said today it would demand the immediate release of the British troops. German Foreign Minister Frank-Walter Steinmeier told reporters that Berlin had obtained official confirmation that the troops were under arrest for an alleged border violation.
The German EU presidency would issue a statement later today "demanding the immediate release of the soldiers", he said.