Pakistan is estimated to have more nuclear warheads than India and the two Asian neighbours along with China are increasing their arsenals and deploying weapons at more sites, two eminent American nuclear experts have said.

While Pakistan is estimated to possess 70-90 nuclear weapons, India is believed to have 60-80, claims Robert S Norris and Hans M Kristensen in their latest article 'Nuclear Notebook: Worldwide deployments of nuclear weapons, 2009'.

The article published in the latest issue of 'Bulletin of the Atomic Science' claimed that Beijing, Islamabad, and New Delhi are quantitatively and qualitatively increasing their arsenals and deploying weapons at more sites, yet the locations are difficult to pinpoint.

For example, no reliable public information exists on where Pakistan or India produces its nuclear weapons, it said.

"Whereas many of the Chinese bases are known, this is not the case in Pakistan and India, where we have found no credible information that identifies permanent nuclear weapons storage locations," they said.

"Pakistan's nuclear weapons are not believed to be fully operational under normal circumstances, India is thought to store its nuclear warheads and bombs in central storage locations rather than on bases with operational forces. But, since all three countries are expanding their arsenals, new bases and storage sites probably are under construction," the two nuclear experts said.