Dr Abdul Qadeer Khan, father of Pakistan's nuclear programme, on Sunday denied that Islamabad or his laboratory were linked to the alleged plans found on Swiss engineers to make nuclear weapons.
The Swiss government said last month that three engineers were found with "detailed plans of how to make nuclear weapons" when they were arrested four years ago on suspicion of smuggling nuclear secrets to Libya.
Qadeer told Swiss newspaper NZZ am Sonntag that although he knew the engineer, named by the paper as Urs Tinner, and his two sons for more than 30 years, the plans were not connected to his programme.
"Pakistan and the Khan Research Laboratories have absolutely nothing to do with whatever Tinner or his sons had on their computers," he told the newspaper in a written interview.
"I have known the Tinner family since 1976 and would not hesitate for a moment to stick my hand in the fire for them," he added. The three engineers were arrested in Germany in October 2004 and then extradited to Switzerland in May 2005.
The father was released in 2006 but the sons are still in prison. The Swiss government faced a storm of criticism after saying that it had destroyed the documents last November "to prevent them from falling into the hands of a terrorist organisation or non-authorised state". Politicians as well as a judge criticised the government over its decision, the judge calling the action "outrageous".