Ms Rice, who appeared on several Sunday television talk shows, said Washington still had a number of diplomatic steps it could take through the UN Security Council against Iran. However, if the Council did not act quickly enough, Washington and its allies would not wait, said Ms Rice.

The US Secretary of State accused Iran of "playing games" with the international community, saying Tehran had had plenty of time to comply with earlier demands to halt its programme.

The United States contends that Iran is working to develop nuclear weapons, but Tehran says its programme is purely to meet civil energy needs.

The United States, Britain and France want to introduce a new Security Council resolution, which would require Tehran to abandon uranium enrichment. The

International Atomic Energy Agency (IAEA) reported last week that Tehran had defied an earlier Security Council deadline to halt its enrichment programme.

Iran renewed its defiant stance on Sunday, vowing to ignore any such resolution and to strike back if attacked.

Reuters