Dr Abdul Qadeer Khan, the father of Pakistan's atom bomb, is being questioned about reports of possible links between the Pakistani and Iranian nuclear programmes, the Pakistani government said today.
The move follows investigations by the UN's nuclear agency. Tehran has acknowledged using centrifuge designs that appear identical to ones used in Islamabad's nuclear weapons programme.
Foreign Ministry spokesman Mr Masood Khan said Dr Khan was being questioned in connection with the "debriefings" taking place of several scientists working at his Khan Research Laboratories, a uranium enrichment plant near Islamabad. "He is too eminent a scientist to undergo a normal debriefing session," Mr Masood Khan said. "However, some questions have been raised with him in relation to the ongoing debriefing sessions."
The spokesman denied reports that Dr Khan was "under restriction" and gave no other details.
Several intelligence sources said however the scientist, who is a national hero for developing a nuclear bomb tested in 1998 to rival India's, had not been allowed to receive visitors at his home in Islamabad nor to leave it since last week.
One intelligence official said the US Federal Bureau of Investigation had taken part in the questioning.
Tehran, accused by Washington of trying to develop nuclear weapons, told the IAEA it had got them from a "middleman" whose identity the agency had not determined, a Western diplomat told Reuters at the time. Pakistan, a key US ally in the "war on terror", denies exporting nuclear technology and specifically denies any link to Iran's nuclear programme. Opposition politicians have condemned the investigations as a "national insult" and a capitulation to American pressure.
It was inevitable the spotlight of the Iran probe would turn to Dr Khan, who worked in the 1970s at a uranium enrichment plant run by British-Dutch-German consortium Urenco. According to diplomats close to the Vienna-based IAEA, the centrifuge designs used by Iran were of a machine made by the plant in the Netherlands.
In 1983, after his return to Pakistan, Dr Khan was sentenced in absentia to four years' jail by an Amsterdam court for attempted espionage, a decision later overturned on appeal.
Earlier this year, Washington announced commercial sanctions on Khan Research Laboratories for allegedly arranging the transfer of nuclear-capable missiles from North Korea to Pakistan, a decision Islamabad protested.