Britain sought international help to isolate Iran yesterday in a standoff over the capture of 15 military personnel in the Gulf and Iran responded by putting off the planned release of a woman captive.

Iran's decision appeared to indicate no speedy end to the dispute, which has stoked Middle East tensions, already heightened over concerns about Iran's nuclear ambitions, and sent shockwaves through the oil market.

Britain insists its 15 sailors and marines were seized last week in Iraqi waters and has published what it says is proof from a global positioning system readout.

An Iranian naval official was quoted by IRNA news agency as saying the Britons' boats entered Iranian territory several times before they were seized and Iran had film to prove it.

"The release of a female British soldier has been suspended," Iran's Mehr news agency quoted military commander Alireza Afshar as saying. "The wrong behavior of those who live in London caused the suspension."

Oil prices remained near six-month highs on concerns that any escalation could hit crucial oil supplies from the Gulf.

The United Nations hit Iran with sanctions at the weekend over its nuclear program. Washington and London also blame Iran for backing insurgents battling their forces in Iraq.

"With the excuse of controlling ships that go to Iraq, they want to make it a norm to violate other countries' sovereignty," Ali Larijani, the secretary of Iran's Supreme National Security Council, said on state television.

"But they should know that the cost of this is not cheap."

Britain is seeking approval from the UN Security Council for a statement deploring the detention of the sailors and government sources said Britain would discuss practical measures at an EU foreign ministers' meeting this weekend.

Prime Minister Tony Blair's official spokesman said Britain was not seeking a confrontation with Iran and wanted the standoff resolved as quickly as possible.

Analysts said they suspected Iran wanted the diplomatic wrangle to take the international focus away from its nuclear energy program.

Britain has halted all official travel between the UK and Iran and suspended visa issuing and support for trade missions. Western partners have not taken specific actions but leaders in Washington and the European Union voiced strong support.

"We have widened the net of arguing our case. First of all we've brought in the EU. Today we're doing so at the UN," Blair's spokesman said.

Iran's Foreign Ministry spokesman Mohammad Ali Hosseini was quoted by IRNA news agency as saying: "Interference of sides who are not related to the issue will not help resolve the issue."

Source: China Daily/agencies