Washington ? A suspected mobile biological weapons lab has been recovered in northern Iraq, a development that senior U.S. officials said Tuesday would lend support to Bush administration claims of a banned weapons program by the government of deposed Iraqi president Saddam Hussein.

A senior administration official said the Pentagon today would announce the results of a two-week investigation into a tractor-trailer truck stolen from a government depot in the northern Iraqi town of Mosul and later handed over to U.S. forces.

The official said the truck and the equipment inside it had been cleaned with bleach and therefore did not show any identifiable residue of biological agents. But intelligence analysts have concluded that “there doesn’t seem to be any legitimate use for it, other than as a biolab.”

The existence of Iraqi weapons of mass destruction programs, in violation of United Nations resolutions dating to 1991, formed a major part of the Bush administration’s rationale for invading Iraq and overthrowing Saddam.

But the administration has been unable to point to concrete evidence of illegal Iraqi weapons activity, nearly a month after the fall of Baghdad to U.S. forces.

The truck-mounted lab is of the type described by Secretary of State Colin Powell to the U.N. Security Council in February, when he outlined what he said was a pattern of concealment by the Iraqi government.