The briefing by retired Lieutenant General Khalid Kidwai, Director-General of the Strategic Planning Division came hard on the heels of assertions by President Pervez Musharraf in Europe that such scenarios were impossible.

"We have instituted command and control structures and security measures in a manner so as to make these foolproof," said Kidwai, who retired from the army in October but not from his position heading the SPD.

"We are capable of thwarting all types of threats whether these be insider, outsider, or a combination."

He said 10,000 troops were deployed around Pakistan's nuclear facilities.

Kidwai said security was heightened after militants began more actively targetting the military in a wave of suicide attacks during the past year.

"The state of alertness has gone up," Kidwai said in a briefing at the SPD Secretariat in the military cantonment area of Rawalpindi, a garrison town next door to Islamabad.

However, no conspiracy or plot related to nuclear facilities had ever been uncovered, he said, though in years gone by al- Qaeda had shown an interest in acquiring a nuclear weapon.

Kidwai, who has headed the SPD since its inception in 1999, has given three similar presentations to foreign diplomats and Pakistani media during the past few months in response to anxiety that instability in the country raised the risk of militants getting hold of nuclear weapons or material for a 'dirty bomb'.

Kidwai said there was an exhaustive vetting process, involving political, moral and financial checks and psychological testing for staff working in nuclear facilities, and security monitors kept especially close tabs on some 2,000 scientists working in ultra-sensitive areas.

He said the nuclear proliferation scandal that broke in 2003, revolving around Abdul Qadeer Khan, a scientist regarded as the father of Pakistan's bomb, was a closed chapter and there was no evidence to suggest any members of the military establishment had been involved.