A senior Pakistani military official says Pakistan wants to put what he calls the "sordid chapter" of proliferation by one of its top scientists behind it and build civilian nuclear ties with the United States.

But he says Pakistan is not ready to make the nuclear scientist, Abdul Qadeer Khan, available for direct questioning over his sale of nuclear parts and secrets to states including Iran, Libya and North Korea. He said there are reasons of national sensitivities for not making him available.

The Pakistani official was giving a background briefing to a small group of reporters in Washington. 

Khan admitted in 2004 that he operated a worldwide clandestine network to sell nuclear technology in the black market.  He was placed under house arrest in Islamabad, but not jailed because he is considered the father of Pakistan's nuclear bomb.