A number of senior nonproliferation experts have left the Bureau as a result, further exacerbating the staffing shortage.

"I think it would be absolutely shocking that they not have some idea," said George Perkovich, a nonproliferation expert at the Carnegie Endowment for International Peace in Washington.

Mr. Clinton's advisers are also urging that he approve the sale of a supercomputer for meteorological purposes that some nonproliferation experts in the Administration fear could be put to military uses.

Joseph Cirincione, a nonproliferation expert at the Carnegie Endowment for International Peace, stood in the lobby looking pleased.

But there are significant omissions, Administration officials and nuclear nonproliferation experts said.

While Congress struggles over renewing aid to Pakistan despite its nuclear weapons program, nonproliferation experts grapple more broadly with how to maintain restraints.

Former American intelligence and nonproliferation experts said the C.I.A. was aware of some, but not all, of these activities, and began tracking scientists at the Khan laboratory.

American nonproliferation experts said the items Mr. Khan sought to buy also had military applications.

Syrian chemical weapons production facilities have been identified by Western nonproliferation experts at approximately 5 sites, plus one suspected weapons base:

Western nonproliferation experts believe China has provided Pakistan with a nuclear warhead design, ballistic missile aid and help with a plutonium production reactor.