"I am not going to discuss hypotheses which I do not believe are going to arise," Straw said when asked what Britain's position would be if Washington were to take military action against Tehran.

The United states has "not taken any option off the table, but in practice, both President George Bush and Secretary of State Condoleezaa Rice say they are pursuing the diplomatic option as vigorously as the Europreans and Russia and China," he told reporters in Riyadh.

Straw was speaking at a press conference with his Saudi counterpart, Prince Saud, after they opened a Saudi-British conference in the kingdom's capital.

He had told BBC radio earlier that Iran's efforts to split the United States and its allies in their bid to halt its disputed nuclear programme have had the opposite effect.

"At each stage they (the Iranians) have calculated they can split the international community ... They have simply ended up with an international community more united in its concern to ensure full compliance by the Iranians," Straw said.

In Tehran, hardline President Mahmoud Ahmadinejad warned Tuesday that Iran's army was like a "meteorite" that would destroy any attacking force. "It will cut off the hand of any aggressor and leave the enemy covered in shame."

Washington accuses Iran of working secretly to build nuclear weapons under cover of a nuclear energy program it is developing with Russian assistance.

Iran denies this charge and says the program is strictly for producing nuclear energy. It is refusing to comply with a UN Security Council demand to freeze sensitive enrichment work.

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