The United States has periodically expressed concern that nuclear weapons and materials in Pakistan could land up in the hands of terrorist organisations. This concern has become more aggravated with the development of tactical weapons which will be distributed to the lowest rung of the Pakistani army.

Only last week, US authorities reiterated their apprehension of potential contact between Pakistan’s nuclear scientists and extremist groups. This is a matter of great concern for the Indian defence establishment which remains sceptical about whether Pakistan will be able to keep its nuclear weapons safe from terrorists.

Both India and Pakistan continue to share a volatile border, with cross-border firing having stepped up during the Modi regime. India is only too aware that Pakistani army is using asymmetrical warfare whereby terrorist networks are used by the military and ISI to further their objectives.

But given that Pakistan is believed to have the fifth-largest nuclear arsenal in the world, the question is just how secure are their nuclear assets given the fear that a 'dirty bomb’ could land up in the wrong hands?

Security expert Dr Bharat Karnad, Research Professor in National Security Studies at the Centre for Policy Research and author of two books on India ‘s nuclear policy, says, "The concern of a rogue nuke has been there for some time. This is a matter of concern for the Indian government. What can you do? There is always the possibility of terrorists taking over a nuclear installation," said Dr Karnad.

But he went on to emphasise, "Pakistan’s nuclear assets are looked after by the Strategic Arms Division. SAD has its own security organisation which is extremely professional...The Pakistan army is an extremely professional one and its nuclear assets are its crown jewels. There is no way they will allow these to be made vulnerable. The Pakistan army has insulated both the ISI and the SAD from Taliban outfits."

To a question on whether China has any access to Pakistan’s nuclear assets, Dr Karnad replied, "China has no say in their nuclear program. China is only a supplier. The plutonium producing reactors in Khushab have been set up with Chinese assistance.’

On the issue of India’s response to a rogue attack, Dr Karnad said, "Unlike Pakistan, India’s own Ministry of Defence is not in the picture. Nuclear response is in within the ambit of the PMO and the NSA."

Dr R Rajaraman, emeritus professor of theoretical physics at JNU and co-chair of International Panel in Fissile Materials believes Pakistan’s heavy water reactors at Khushab can together produce only 105 kg of Pu in a period of five years and there is no way they can reach the figure of 200 warheads by 2020 as has been projected by some security analysts.

On the crucial issue of these weapons falling into the hands of terrorists, Dr Rajaraman replied, "I don't think terror groups like the Taliban can get their hands on a Pakistani bomb. They may have launched some attacks at the gates of some military bases. But that is a far cry from penetrating the rings of security that Pakistan must undoubtedly have to guard its weapons."

Dr Rajaraman is more concerned about the use of the Nasr missiles given that there is no clear command and control status of these battlefield nuclear missiles. He goes on to say, "Because it is a battlefield weapon, there is an increased possibility of terrorists getting hold of it in transit or in the heat of battle and that can be an extremely dangerous development."

Elaborating on this point, Dr Rajaraman maintains that while the `button’ is controlled by a collection of people from the apex political and military sections of Pakistan, how this chain of command will prove effective in a battlefield weapon is a different issue.

He further said, "The field commander will be given some level of on-the-spot decision making on its launch but this also increases the probability of an accidental development. Its use represents a very unwise move which raises the level of nuclear danger in the subcontinent,’ he added.

Dr Anil Kakodkar, former chairman of the Atomic Energy Commission, believes that the apprehension of nuclear weapons falling into the hands of terrorist groups is not misplaced. "I think we have to be always on the alert on how to deal with such situations and our response to such a development will naturally be very complex,’ said Dr Kakodkar.

He refused to spell out what this response mechanism would be except to say, "We have enough mechanisms in place to deal with such a situation….. We can only hope that anyone who acquires nuclear weapons shows higher degrees of responsible behaviour,’ said the eminent scientist.

Prof Srikumar Banerjee, Chancellor, Homi Bhabha National Institute and former chairman of the Atomic Energy Commission, is circumspect about such a development. He believes multiple checks are maintained in the national boundaries of nations with nuclear arsenal and nuclear materials.

"The safety of this material is the responsibility of the concerned governments. That is why every nuclear reactor or production facility is protected and the material counted down to the last milligram,’ said Banerjee.

Citing the example of India, he said, "There is complete accounting which is done very vigorously and cannot be deviated from. The International Atomic Energy Agency has also laid down very strict norms which each nation has to follow.’

Prof MV Ramana,theoretical physicist, who has authored a book on India's nuclear power does not rule out the possibility of non-state actors acquiring nuclear weapons.

Prof Ramana said, "I don't think one can rule out the possibility of non-state actors in Pakistan or, for that matter, in India, obtaining nuclear weapons. However, they do not, as far as I know possess any nuclear weapons. Nor do I think will it be easy for them to get their hands on nuclear weapons. All countries try to protect their nuclear weapons to the extent possible."

On several occasions, Pakistani intellectuals have also expressed their apprehensions on this possibility. Pakistan Air Commodore Tariq Ashraf’s book Evolving Dynamics of a Nuclear South Asia highlights the absence of a civilian and bureaucratic involvement in Pakistan Nuclear Control Authority.

Other neighbouring countries apart from India are concerned about the likelihood of such an event. It has now come to the fore that following the Taliban attack on an army-run school in Peshawar three years ago, Pakistan’s Atomic Energy Commission wrote a letter to the SPD expressing concern about such a development given that Pakistan is home to hundreds of terrorists.

Former Pakistani president Pervez Musharraf has gone to the extent of claiming that nuclear stockpiles were not being collected to be used at the time of a festival. Meanwhile, even as Pakistan maintains its nuclear force is being built up to deter a conventional attack by India, it is also being used as a cover for terrorist attacks it sponsors in India such as the infamous Mumbai attack.