Counsel for the nuclear scientist and government spokesmen were not immediately available for comment.

Khan, 72, complained that he was confined to his house under the pretence of a security protocol which required him to seek permission to move around and meet guests.

The nuclear scientist, who is celebrated as the father of Pakistan's atomic bomb, has been under virtual house arrest since early 2004 when he confessed to participating in nuclear proliferation.

He was immediately pardoned by then president Pervez Musharraf after the televised confession.

A court in Islamabad in February declared Khan 'a free citizen', subject to a security protocol agreed with the government.

The US government described Khan as 'a serious proliferation risk'.