THE founder of Pakistan’s nuclear weapons program claims that in the late 1990s North Korean officials paid kickbacks to Pakistani military figures in exchange for critical weapons technology.

ABDUL Qadeer Khan has passed documents to a US-based expert that appear to show North Korea’s government paid more than $US3.5 million ($3.26m) to two Pakistani military officials as part of the deal.

Dr Khan released what he said was a copy of a North Korean official’s 1998 letter to him, written in English, that purports to describe the secret deal.

Dr Khan admitted in 2004 that he had passed atomic secrets to North Korea, Iran and Libya, but later retracted his remarks and in 2009 was freed from house arrest. Those secrets are believed to have allowed North Korea to develop a uranium route alongside its existing plutonium weapons program.

Dr Khan gave the documents to Simon Cameron of the Washington Institute for Near East Policy, an authority on Pakistan’s weapons program. He did so because he has been accused by his government of running a covert nuclear smuggling operation.

“He gave it to me because he regarded it as showing that the story, the perception that he had been a rogue operator, was false,” Mr Cameron said.

The letter, along with a statement by Dr Khan describing the deal, suggests that at least some top-level Pakistani military officials knew early on about Dr Khan’s involvement in the sale of nuclear weapons technology.

If true, it could deepen the distrust between the US and Pakistan in the battle against militants in Afghanistan and Pakistan.

Mr Cameron said the documents prove Dr Khan’s claims that his smuggling network had high-level support from the Pakistani government, but others say the letter bolsters the government’s claims it did not know what Dr Khan was doing. The Washington Post said it first reported on the documents on its website this week after a lengthy effort to authenticate them.

Dr Khan’s letter is dated July 15, 1998, and marked “Secret”. It carries the apparent signature of North Korean Workers’ Party secretary Jon Byong Ho.

The text says: “Please give the agreed documents, components, etc. to a . . . (North Korean Embassy official in Pakistan) to be flown back when our plane returns after delivery of missile components.”

The letter never mentions the word nuclear. But Dr Khan’s written description of the events surrounding the letter makes it clear that the Workers’ Party official was referring to components and plans for Pakistani centrifuges used to enrich uranium.

Jehangir Karamat, a former Pakistani military chief named as the recipient of the $US3m, said the letter was untrue. Dr Khan, as part of his defence against allegations of responsibility for illicit nuclear proliferation, had tried “to shift blame on others”. The other official, retired Lieutenant General Zulfiqar Khan, called the letter “a fabrication.”

The Post said the assertions by Dr Khan and the details in the letter could not be independently verified. But it quoted one senior US official, who said the signature appeared genuine and the contents were “consistent with our knowledge” of the events described. Another intelligence official said the letter contained information known only to a handful of people.