"The developing picture, however, indicates that the Khan network received at least $100 million for supplying technology, equipment and know-how" to Libya, he said.

But American officials have also suspected that the Khan network provided Iran with a warhead design as well.

The warhead design provided to Libya by the Khan network was for an aging, crude Chinese model.

President Bush boasts that the Khan network has been dismantled.

"We're getting an idea of how it works," he said of the Khan network.

It has about a half dozen specialists looking for evidence of deals by the Khan network or its imitators.

Last year, Pakistan said its investigation into the Khan network was closed.

But scraps of evidence gathered by the international agency and the accounts of some members of the Khan network have cast doubt on those denials.

Investigators say that document, too, appears to have come from the Khan network.

More recently, investigators have found that the Khan network had offered similar materials to Iran.