"We're finding now that the capabilities are even more dispersed and disguised than we thought," Armitage said in a speech at the National Defense University.

"It's going to take us months to find this material, but find it we will."

A coalition led by the United States and Britain ousted the regime of Saddam Hussein, claiming it was developing banned nuclear, biological and chemical weapons after failing to convince the UN Security Council to take tougher measures to force Saddam to disarm.

Iraq -- which denied possessing banned weapons -- had been under UN sanctions stemming from its August 1990 invasion of neighboring Kuwait.

Saying the invasion was a last resort after all other means of disarmament had failed, Armitage called for more effective international efforts to stop proliferation of nuclear, biological and chemical weapons peacefully.

"Iraq is an object lesson that can happen if you leave the problems of proliferation to the solutions of the past," he said.

But Washington and London have come under fire in recent weeks because little proof of their accusations have emerged, despite frequent tips and searches.

Washington also has refused to accept a return of UN weapons inspectors, assembling its own team of 1,000 experts to search Iraq for banned arms.

Chief UN weapons inspector Hans Blix, who has lobbied hard for a return of his team to Baghdad, has accused Washington of using "shaky intelligence" -- including forged documents -- to justify the invasion.

Other critics include France and Russia, where President Vladimir Putin noted with sarcasm that "two weeks after the end of the conflict, no weapons have yet been found" during a visit Tuesday by British Prime Minister Tony Blair.

Armitage dismissed the criticism, saying. "I'm extraordinarily confident that Iraq had those capabilities.

"It's far too easy to hide and move these capabilities and far too difficult to find them."

He said the recent capture of key Iraqi officials had aided the search. Among those captured in recent days are General Hossam Mohammad Amin, Saddam's liaison with UN inspectors, and Amer Mohammad Rashid al-Ubaidi, a former oil minister and weapons adviser.

"The people we have found are already leading us to other people, as well as computer files and documents," Armitage said.

US officials previously have suggested Saddam may have ordered the destruction of some of his illicit weapons when it became clear that he would face an imminent invasion. They also have raised concerns some of the weapons or technology had been smuggled to other countries, particularly Syria.

SPACE.WIRE