A British think-tank specialising on Pakistan's security issues has said that the chances of Islamabad's nuclear assets falling into the hands of tribal militants have increased as most of the arsenals are located in the restive north-western parts of the country.

The Pakistan Security Research Unit in its report, 'The Security of Nuclear Weapons in Pakistan', said Islamabad had in place robust measures but each contained some weaknesses and many were being exacerbated by the present political turbulence in the country.

In his report, PSRU chief Professor Shaun Gregory claimed that to assure the security of its nuclear weapons against an Indian threat, Pakistan established many of its nuclear weapons sites in the country's northern and western parts.

"But this had the unintended consequence of placing them close to areas which are presently dominated by Taliban and tribal militants groups," the PSRU chief said in the report released in London [Images] on Wednesday.

He said these tribal and pro-Taliban militants might launch an assault against a part of Pakistans nuclear weapons infrastructure.

"They may seek to take possession of nuclear weapons or components, but they could also seek to create a radiological hazard by using explosives or fire to try to destroy the weapons," said the think tank established in the Department of Peace Studies at the University of Bradford, UK.

It argues that while robust measures are in place to prevent the weapons or weapons components from falling into extremist/terrorist hands, these measures cannot provide complete assurance against that possibility.

"In the present context of political instability President Pervez Musharraf's [Images] control may be weakening and Pakistan may become even more porous in leaking nuclear secrets," the report said.

The PSRU report noted that there existed growing antipathy in the Pakistan Army and intelligence agencies to the West and growing sympathy for some extremist/terrorist groups.

It was feared that this raised the possibility that nuclear weapons security could be compromised by collusion either between renegade military personnel or between such personnel and extremists/terrorists.

Based on comparable data from the US, the report said, "This may mean that 1 in 25 of those in Pakistan with nuclear duties are unreliable at any one time, though not all these will constitute a threat to nuclear weapons security."

Indicating that Pakistan may have as many as 120 nuclear weapons in its arsenal, the think tank argues that should the situation in the country further disintegrate the security of the strategic arsenals may be compromised.

Established in March 2007, PSRU conducts interdisciplinary research on all aspects of Pakistani security, with particular emphasis on extremism/terrorism and nuclear weapons issues.