Campaign spokesman Mark Kitchens told AFP that the White House's "arrogant unilateralism" had made it harder to get the necessary cooperation from European allies and the UN nuclear watchdog to rein in Iran's ambitions.

He made his comments a day after a State Department spokesman expressed alarm over Iran's admitted program of uranium enrichment and declared that Tehran was making an "unrelenting push toward nuclear weapons capability."

"Recent developments represent another national security failure for the Bush administration," Kitchens said as the Kerry campaign sharpened its attacks on President George W. Bush six weeks before the November 2 election.

Kitchens said the administration had lost its bid for a tougher International Atomic Energy Agency (IAEA) resolution that would have referred concern over Iran to the UN Security Council.

"Now we learn that Iran will not even comply with the IAEA resolution and has begun uranium enrichment activities," he said.

"We must make clear to Iran that the United States will lead an international effort to push for tougher measures, including sanctions, if they do not comply with the IAEA resolution," Kitchens said.

Contacted for comment, the Bush campaign had no immediate response.

Both Bush and Kerry have publicly given a high priority to preventing the spread of nuclear weapons. But neither side has offered any new solution for dealing with Iran and neither has spoken of possible military action as in neighboring Iraq.

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