"A Q Khan is history," Pakistan Foreign Minister Shah Mahmood Qureshi said, claiming that the Pakistan authorities had broken his nuclear smuggling network and extracted all the information from him.
"A Q Khan has no say or access to any of the sensitive areas of Pakistan," Qureshi said in remarks broadcast by the Dawn television.
Khan, who once confessed to passing nuclear know how to Iran, Libya and North Korea was set free from five years of house arrest after a court declared him a "free citizen", following a secret agreement with the government.
The move has alarmed New Delhi, Washington, London, Paris and other major powers.
The White House said that United States President Barack Obama wants assurances from Islamabad that AQ Khan is no longer involved in the activities that led to his arrest, while the US State Department said Khan remained a serious proliferation risk.
Qureshi also said that, "Pakistan had put in place a foolproof command and control authority and our nuclear assets are safe."
AQ Khan was detained in December 2003 after he admitted on state-run television that he operated a network that spread nuclear weapons technology around the world. However, unanswered questions remained about with whom Khan allegedly shared the nuclear know how and whether Pakistani authorities knew about it and profited from it.