WASHINGTON, March 10: The United States urged Pakistan on Wednesday to scale back its missile programme after it test-fired a ballistic missile capable of carrying nuclear warheads.

"We continue to urge Pakistan and other countries in the region to exercise restraint in their nuclear weapons and missile programmes, as part of an ongoing effort to relieve tensions and build confidence in the region," State Department spokesman Richard Boucher said.

On Tuesday, Pakistan tested its Shaheen-II missile with a reach of 2000 kilometres, exceeding the range of Pakistan's previous longest-range missile that could travel up to 1500 kilometres.

Commenting on the test, defence experts in Washington said it was a display of Pakistan's adherence to the theory of nuclear deterrence in South Asia. Robert Einhorn, a senior adviser for international security at Washington's Center for Strategic and International Studies, believes the test was "completely independent of the controversy involving Pakistani scientists who exported nuclear materials to Iran, Libya and North Korea."

By testing the missile, Pakistanis made it clear that "they want to continue to pursue their deterrence capability. It's an indication that they are moving forward," said Mr Einhorn.

Mr Krepon of the Henry L. Stimson Center proposed some measures he believes can help reduce the nuclear threat in the South Asian regions. These include: "an agreement only to test missiles from designated test ranges and in a direction away from the other country, to provide normal notification with longer time, range of flight tests and prior notification of when missiles are moved from their bases." Currently, India and Pakistan notify each other two to three days before conducting a test.

"Missile flight testing is not going to stop in South Asia, what can be done is to reduce anxiety and to clarify non-threatening postures," said Mr Krepon. "What Pakistan does after the resumption of talks with India will demonstrate it is a responsible country.

A responsible state does not attach nuclear risk reduction to Kashmir. It does not call Kashmir a nuclear flash point. It can demonstrate its responsibility by ending jihadi groups that are crossing the Line of Control," Mr Krepon said.