The White House says the discovery of parts of an Iraqi uranium-enrichment program shows that Saddam Hussein was lying about weapons of mass destruction.

White House spokesman Ari Fleischer says the former head of Iraq's uranium enrichment program, Mahdi Obeidi has turned over documents and centrifuge parts that were hidden in his garden since 1991.

"Dr. Obeidi told us that these items, the blueprints and the key centrifuge pieces, represented a template for what would be needed to rebuild a centrifuge uranium-enrichment program," he said. "He also claimed that this concealment was part of a secret, high-level plan to reconstitute the nuclear weapons program once sanctions had ended."

Mr. Fleischer says the evidence shows that Iraq's weapons declarations to the United Nations before the war was false, and there was what he calls "a very substantial and effective" program to conceal weapons and deceive U.N. inspectors.

The International Atomic Energy Agency says the discovery of equipment buried more than 12 years supports its conclusion that Iraq has no recent nuclear weapons program.

Preventing the spread of weapons of mass destruction was one of the biggest reasons President Bush gave for invading Iraq. More than 10 weeks after the fall of Baghdad, Mr. Bush and his ally British Prime Minister Tony Blair are facing questions about why those weapons have not been found.

Mr. Fleischer said the discovery illustrates what he calls the "extreme" challenges of finding weapons designed to be hidden.

"We are hopeful that this example will lead to other Iraqi scientists stepping forward to provide information," he said. "We have maintained right from the beginning that the best way, based on the history of what was discovered in the '90s, to obtain information is as a result of Iraqi's providing information to the United States just as this Iraqi scientist has."

Mr. Fleischer says Dr. Obeidi was interviewed by IAEA inspectors in 2002, but did not reveal the hidden materials because he feared for his life.

Mr. Fleischer says that is why the United States insisted, before the war, that U.N. inspectors take Iraqi scientists and their families outside the country for interviews so they would not be intimidated.