Powell told reporters Wednesday night the United States will urge the United Nations' nuclear watchdog group on Sept. 13 in Vienna to refer the Iranian case to the UN Security Council for action.

"We're looking at the range of possible actions of a political, economic, diplomatic nature," Powell said.

He commented while flying home from Panama after attending the inauguration of Panamanian President Martin Torrijos.

In Vienna, the UN's International Atomic Energy Agency said earlier Wednesday that Iran plans to process tons of raw uranium and restart its centrifuges two activities that could be used to make nuclear warheads.

US diplomats at the meeting said the revelations provided further evidence that Iran's activities pose "a threat to international peace and security."

"Unless there are assurances that the international community can count on, I think it's appropriate that it (the Iran issue) be referred to the Security Council," Powell said.

He said it remains to be seen whether there is a consensus to do that now.

AFP adds: Iran was emboldened yesterday and determined to advance its nuclear activities after the UN nuclear watchdog again failed to produce a "smoking gun" confirming US allegations of a secret weapons drive.

The latest report from the International Atomic Energy Agency (IAEA) said it was "plausible" that Tehran was telling the truth in claiming that uranium contamination found by IAEA inspectors had come from imported equipment and not because Iranian authorities were enriching uranium at the suspect sites as material for an atomic bomb.