NEW YORK, July 29: The Bush administration has for the first time presented North Korea with specific ‘evidence’ behind American allegations that it secretly obtained uranium enrichment technology from the founder of Pakistan’s nuclear programme, the New York Times said, quoting two senior administration officials.

The officials told the newspaper that “the decision to share the intelligence with North Korean negotiators was part of an effort to convince North Korea that any discussions about disarmament must cover not only the nuclear weapons program it has boasted about, but a second one that it now denies exists”.

Putting on the table the evidence that North Korea obtained technology from the network built by Dr Abdul Qadeer Khan is significant because it is an effort to break an impasse over the scope of North Korea’s nuclear programme.

American officials were reluctant to describe the North Korean response, but one official told the paper that when presented with the evidence “they argue with us about it.”

American officials have never made public details of Dr Khan’s statements to Pakistani officials, who have declined to make him available for direct interrogation. But they have shared the information widely with Asian allies, and elements of it have leaked out, including Dr Khan’s assertion — doubted by several specialists in the American intelligence community — that the North Koreans once showed him what they said were three fully assembled nuclear weapons, the newspaper said.

The two Bush administration officials declined to speak on the record, citing the delicacy of both the intelligence and the current negotiations. They would not describe how much detail had been given to the North Koreans.

The presentation came in the first two days of talks in Beijing, which American officials said might stretch into next week. On Thursday, American negotiators, led by Christopher R. Hill, moved past generalities in talks with North Korea and focused on the specifics of their dispute over the nuclear programme.

In February, North Korea declared for the first time that it was a nuclear weapons state. It said it had reprocessed 8,000 fuel rods, turning them into weapons fuel. Specialists inside and outside the government say that fuel could be used to produce six or more nuclear weapons, but there is no independent evidence to confirm that the weapons have been produced.