John Wolf, assistant secretary of state for non-proliferation issues, also said Europe needs to stand "shoulder to shoulder" with Washington to combat such arms, lamenting that this was not the case in Iraq.

"We're 39 days after the start of the war. (Iraq) is a country that spent a lot of time burying, hiding, deceiving, breaking its program into pieces," he told reporters in Brussels.

"We are confident that with time, with careful work, that we will unravel the mystery and... demonstrate what we know to be the case, which is that they had a weapons of mass destruction program."

Wolf said that intelligence -- from Iraqi officials or documents -- was crucial to finding such arms.

"We just can't go around digging holes in the ground and expect that under every rock there is a WMD," he said.

"Under some rock, or rocks, and in caves or broken into pieces or in factories that have other purposes we will identify the WMD capability.

"It will be there, and we're quite confident, but we're not going to say that it's going to happen on day 39 or whether it's going to happen on day 60."

In other comments, Wolf also said that Europe and others need to maintain a united international front to defeat the threat of such weapons, noting in particular Iran and North Korea.

"In the end the proliferators need to know that they risk isolation, and we need to stand shoulder to shoulder on this sort of stuff. Iraq was unfortunate in that respect. We didn't stand shoulder to shoulder," he said.

Europe could use its diplomatic influence to press countries that support extremists, he said, noting the EU's dialogue with Iran -- which is on Washington's "axis of evil."

"Using the Union's diplomatic weight with... countries that pose vexed, troubling questions as well as with supplier countries is an important part" of a solution to the problem, he said.

SPACE.WIRE