"All United States presidents always say all options are open, but it is not on the table, it is not on the agenda. I happen to think it is inconceivable," Straw told BBC radio from the Labour Party conference in Brighton.

US President George W. Bush has refused to rule out any option in dealing with Iran amid fears it seeks to produce nuclear weapons.

The UN atomic watchdog, the International Atomic Energy Agency, passed a resolution Saturday in Vienna that opened the door to reporting Iran to the UN Security Council for violating international nuclear safeguards.

The vote on a resolution drafted by EU negotiators Britain, Germany and France signalled an escalation of the face-off with the Islamic Republic, raising the prospect of UN sanctions if further diplomacy fails.

Straw, whose government currently holds the rotating EU presidency, said the resolution demonstrated that the European Union had gained an international consensus on the Iran nuclear issue.

"We have ensured that we've had the United States fully backing us on this diplomatic route," he said.

Referral to the Security Council would come only after a report on Iran by IAEA chief Mohammed ElBaradei, which he will probably make to the next board meeting in November.

"We left the door open for further diplomatic action with Iran. And I hope they take this opportunity," Straw said.