The meeting at the Central Intelligence Agency's headquarters in Langley, Virginia, near Washington, was "related to the need to discuss ways and means to curb the nuclear black market and trafficking in nuclear materials and parts," International Atomic Energy Agency (IAEA) spokeswoman Melissa Fleming said.

ElBaradei is to meet in Washington Wednesday with US President George W. Bush.

ElBaradei had said in February that the revelations from Abdul Qadeer Khan, the father of Pakistan's atomic bomb, about a clandestine network for spreading nuclear technology were just the "tip of an iceberg" about such illegal trafficking.

Khan has admitted to leaking nuclear secrets to Iran, Libya and North Korea.

ElBaradei said Khan "was not working alone" and that the whole network must be traced.

He said the IAEA, the UN's agency for guaranteeing nuclear non-proliferation worldwide, in trying to piece together what was "a supermarket" of international smuggling of nuclear materials and information such as weapons blueprints the United States has found in Libya.

ElBaradei had said in February that the IAEA needed more intelligence help from countries like the United States.

"Sometimes information came to us that was not very timely," he said, referring to an agreement the United States and Britain reached with Libya for Tripoli to give up its weapons of mass destruction programs.

ElBaradei said the IAEA didn't know about it "until Libya announced it," in December, after months of secret talks with Washington and London.

ElBaradei said while flying Sunday from Vienna, where the IAEA is based, to Washington that his agency needs more cooperation from Pakistan in its investigation of Iran's atomic program, which is suspected of developing nuclear weapons.

He said he had "been in touch with Pakistan," which has "been cooperating, but I still need more cooperation" from them in allowing "environmental sampling" to compare centrifuge components of a type sold through an international black market to Iran.

Iran claims contamination from particles on the imported components was the source of highly enriched uranium (HEU) discovered by the IAEA at two sites in Iran.

HEU can be used both as nuclear fuel in civilian reactors or as the raw material for an atomic bomb.

Experts who study the IAEA said the international agency has been relying on intelligence from foreign governments since 1993, when a "watershed" event took place in trying to deal with the North Korean issue.

In a presentation to a small group of member states on the IAEA's governing board, the IAEA reached agreement with the CIA to show satellite images of North Korean activities at a nuclear site.

"It was a very important point. It showed how important intelligence could be in making a case," an expert said.

Since then, the IAEA has been anxious to get as much intelligence as possible from its member states, which include the United States and western European countries, the expert said.

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