Iraq accused the United States and Britain on Monday of lying to justify an attack on Iraq, and challenged them to produce "one piece of evidence" that Baghdad is producing weapons of mass destruction.

Iraqi officials also took reporters on two tours in an attempt to refute accusations President Saddam Hussein is rebuilding sites linked to past nuclear efforts and training terrorists.

The head of a U.N. atomic weapons team, Jacques Baute, said Friday that satellite photos show unexplained new construction at several sites the team used to visit when it was still allowed into Iraq for inspections. Baute did not identify the sites in his comments.

British Prime Minister Tony Blair, President Bush's main ally in the Iraq standoff, has cited the satellite photos as proof Saddam had a weapons of mass destruction program that posed a threat.

But Iraqi Foreign Minister Naji Sabri said such assessments from Blair and Bush "are pretexts for ... aggression against our country, they know very well that these are false pretexts, false accusations.

"We challenge them to present one piece of evidence, a single piece of evidence for these accusations."

Bush has threatened Iraq with unspecified consequences if he does not allow the return of U.N. weapons inspectors to certify Iraq is not producing weapons of mass destruction.

Iraq agreed to such inspections after the Gulf War in 1991, but the inspectors left in December 1998, and Baghdad has not allowed them back.