Under new procedures devised by the Pentagon, dismantling could take place without revealing warhead designs.

"The team recommended that a specialized inspection team be scheduled to address all issues of warhead design and testing with Iraq's experts," the report said.

The history of the W47 warhead had a serious series of reliability problems with the warhead design.

To develop a nuclear weapon Iran needs a warhead design, a certain amount of fissile material, and a delivery vehicle such as a missile.

The Congressional report does not name the specific warhead design thought to have been stolen by China.

Work to produce advanced warhead designs was also developed.

American officials say they do not know if Iraq has developed new warhead designs.

ECM protection and warhead design were also modified, as was the ammunition handling system.

But they become more valuable when combined with specific performance data, which would then enable someone to generate a computer simulation of American warhead designs.

The stolen material, including computer codes that are essential to warhead design, most likely came from supposedly secure computers at America's nuclear weapons laboratories.