International Atomic Energy Agency (IAEA) spokesman Mark Gwozdecky said: "We've had excellent cooperation" since Libya agreed in December to dismantle its programs to develop weapons of mass destruction, but added:

"To have a full picture of what happened is going to involve ongoing work, particularly with the black market."

Gwozdecky said "critical questions" remained about whether Libya had made copies of the nuclear weapons designs it has now scrapped.

"We want to know if copies were made," he said. The investigation would focus on "getting information from the source of these (arms design) drawings," which is the nuclear black market run by disgraced Pakistani scientist Abdul Qadeer Khan, he said.

In May, the IAEA said it would continue to investigate Libya's abandoned nuclear program as much to discover new facts about Libya as about the international smuggling network that supplied it.

In a report filed Monday ahead of a meeting of the IAEA board of governors on September 13, the IAEA said it would not be compiling a further report for the next gathering in November, an official, who asked not to be named, said.

The IAEA, the UN organization that verifies adherence to non-proliferation safeguards, has been overseeing Libya's disarmament, which Tripoli agreed to last December 19 with the United States and Britain.

The United States has called on Iran, which the IAEA is investigating on charges of secretly developing atomic weapons, to be as forthcoming about its nuclear program as Libya has been.