According to the letter posted by The Washington Post on its website, which is accompanied by a story, Jon ByongHo, secretary of the workers party of North Korea, in a letter dated July 15, 1998 asks A Q Khan, who then was the project director of the Kahuta Research Center, to give "agreed documents" and "components" to a North Korean embassy official in Islamabad.
In the letter, the authenticity of which according to The Post has been confirmed by senior United States and western officials, Jon says that "3 millions dollars have already been paid to Army Chief General J Karamat and half a million dollars and 3 diamond and ruby sets have been given to Gen Zulfiqar Khan".
Both Karamat and Khan have refuted the allegations.
In an e-mail from Lahore, Karamat said that Khan, as part of his defense against allegations of personal responsibility for illicit nuclear proliferation, had tried "to shift blame on others".
He said the letter's allegations were "malicious with no truth in them whatsoever", The Post said. Khan called the letter "a fabrication".
A senior Pakistani official, who asked not to be named "to avoid offending" Khan's supporters, said the letter "is clearly a fabrication". It is not on any official letterhead and bears no seal.
"The reference to alleged payment and gifts to senior Pakistani military officers is ludicrous," the daily said. The Washington Post said the letter was provided to it by former British journalist Simon Henderson, who the daily verified had obtained it from Khan.
A US intelligence official who tracks nuclear proliferation matters said it contains accurate details of sensitive matters known only to a handful of people in Pakistan, North Korea and the United States, the daily noted.
"If the letter is genuine, it would reveal a remarkable instance of corruption related to nuclear weapons. US officials have worried for decades about the potential involvement of elements of Pakistan's military in illicit nuclear proliferation, partly because terrorist groups in the region and governments of other countries are eager to acquire an atomic bomb or the capacity to build one," the daily said.
Olli Heinonen, a 27-year veteran of the International Atomic Energy Agency who led its investigation of Khan before moving to Harvard Kennedy School last year, said the letter is similar to other North Korean notes that he had seen or received.
They typically lacked a letterhead, he said; moreover, he said he has previously heard similar accounts -- originating from senior Pakistanis -- of clandestine payments by North Korea to Pakistani military officials and government advisers," the Post said.