The Bush administration wants to learn more about the work of Pakistan's disgraced nuclear scientist A Q Khan and his network activities even as Islamabad maintains the matter related to him as "a closed chapter".

"I am not going to get into any specific allegations, but certainly learning more about the work of A Q Khan and his network certainly is something we are interested in. It is a matter of continuing interest for us," US State department spokesman Sean McCormack told mediapersons.

"We have learned a lot. The network is broken up. It is out of business. But I think we, as well as others, are still plumbing the extent of all A Q Khan -- all of the Khan network's activities," he added.

When asked if there is ongoing pressure on Islamabad to allow direct access to Khan, McCormack replied: "I don't know what the most recent discussions were about it. But I know it is a matter of continuing interest for us -- again, determining exactly the full extent of that network's activities, with A Q Khan being at the centre of it."

Pakistan's Foreign Minister Shah Mehmood Qureshi, in an interview to CNN on Sunday, had termed Khan as "history" when asked about the access to nuclear scientist.

"A Q Khan is history. A Q Khan does not enjoy any official status. The information that had to be extracted from him has been extracted, and that's as far as Pakistan is concerned, that is a closed chapter. That is a closed chapter," Qureshi replied.