Pakistan's successful test of a missile able to carry short range nuclear weapons threatens to raise tensions in a region already nervous that the death of Osama bin Laden will create more instability.
Tactical nuclear weapons, as these are called, are often seen as more dangerous than the traditional strategic weapons because of their small size and vulnerability to misuse. Theft makes them a risk to global security.
The biggest concern is that these low yield weapons are seen as less destructive and therefore more likely to be used than other classes of weapons.
Pakistani experts say the country has been forced to develop tactical nuclear weapons because of India's "Cold Start" plan under which Indian troops are primed to carry out a lightning strike inside Pakistan if another Mumbai-style attack is traced back to Pakistan-based militant groups.
The military said it had tested last month the 60-km (36-mile) range NASR surface-to-surface missile.
Security experts in the United States, India and Pakistan said it meant the military planned to deploy these weapons in the battlefield, escalating the regional nuclear competition.
“Pakistan's development and testing of nuclear-capable short-range missiles is a destabilising and potentially dangerous development,” Daryl G. Kimball, the executive director of Arms Control Association, said.
“It suggests that Pakistan would seriously contemplate use on the battlefield in the event of an incursion by Indian forces.”
“Our capability in the area of low yield fission devices is well known,” a former Indian defence scientist involved in the 1998 tests said. India may yet respond by mounting nuclear warheads on its shorter range missiles to meet the Pakistani threat. It tested low yield nuclear devices in 1998 but there has been no word since then on whether it has added them to its arsenal.
Pakistan responded to India's tests with explosions of its own. Pakistan even more and at a pace that Western experts say may, within a decade, make it the fourth largest weapons power, behind the United States, Russia and China.