NEW YORK, April 13: Pakistani nuclear scientist Abdul Qadeer Khan has told interrogators he was shown three nuclear devices at a secret underground nuclear plant when he visited North Korea five years ago , The New York Times reported on Tuesday.

Although US officials were unclear about Dr Khan's ability to discern a real nuclear device from a mock-up, his account, if true, would roughly match previous US Central Intelligence Agency estimates of North Korea's nuclear capabilities, the paper said.

US Vice-President Dick Cheney was expected to cite the intelligence report in his meetings with Chinese leaders on Tuesday in Beijing, the Times said quoting US officials, who declined to discuss it in detail saying it was "too sensitive".

Dr Khan, the paper says, told the investigators he was allowed to inspect the weapons briefly. American intelligence officials caution that they cannot say whether Dr Khan had the time, expertise or equipment to verify the claims.

But they note that the number of plutonium weapons roughly accords with previous CIA estimates that North Korea had one or two weapons and the ability to produce more.

The account of Dr Khan's 1999 visit to North Korea has been provided in classified briefings to nations within reach of North Korea's missiles, Asian and American officials who were briefed by the Pakistanis told the paper. Pakistan does not allow US intelligence agencies to interrogate Dr Khan directly.

Dr Khan also told interrogators he began dealing with North Korea on the sale of equipment for a second way of producing nuclear weapons as early as the late 1980s.

However, he said he began major shipments of equipment for the enrichment of uranium in the late 1990s, after North Korea's plutonium programme was frozen under an agreement with Washington that the secretive communist country has since renounced.

Dr Khan sent Pyongyang both the designs for the centrifuges used to enrich uranium and a small number of complete centrifuges, as well as a "shopping list" of equipment it needed, said the officials briefed by the Pakistanis.

"We think they've pretty much bought everything on the list, with the possible exception of a few components," a US official told the paper.

Dr Khan, according to the paper, also said the secret underground nuclear plant he visited was different from North Korea's main nuclear plant at Yongbyon. "It was about an hour out of the capital (Pyongyang)," a senior Asian official told the daily. "But it's not clear in what direction."