WASHINGTON, Aug 1: The US Senate’s Foreign Relations Committee has been warned that Pakistan is one of the nations whose nuclear programmes posed a continuing threat to US security.

Senator Robert Casey, who chaired the committee’s meeting on non-proliferation on Tuesday, stressed the need to strengthen the nuclear non-proliferation regime to prevent nuclear weapons falling into the hands of terrorists.

Speaking about `the nightmarish scenario of a nuclear weapon exploding in an American city’, Senator Casey observed: “To the extent that states like North Korea and Iran succeed in acquiring nuclear weapons, and unstable regimes like Pakistan continue to expand existing nuclear arsenals, that threat will continue to grow.”

For this reason, he said, the US must renew its efforts to reinforce the nuclear non-proliferation regime and prevent additional states from acquiring the deadliest weapons known to humanity.

Later in the hearing, Senator Casey also mentioned the operating agreement India and the US finalised last week for implementing a historic deal that would allow New Delhi to acquire civilian nuclear reactors and fuel from the United States.

Media reports indicate that the deal allows India to resume nuclear tests and to reprocess spent fuel from US-supplied reactors, freeing fuel from other reactors for making weapons.

“Should we be concerned about the perception of double standard” in concluding a nuclear deal with India, asked Senator Casey.

Andrew Semmel, acting deputy assistant secretary of state for nuclear non-proliferation policy and negotiations, who appeared as a witness, told the panel that there was no need to worry about the repercussions of the Indo-US nuclear deal.

“We’re very pleased that India has made a number of commitments that it would not perhaps have otherwise made in terms of adhering to a number of international standards in the nuclear suppliers group, in the missile technology control regime, and others,” said Mr Semmel.

“So I think one of the net effects of this from a positive standpoint is non-proliferation. And I don’t want to oversell the non-proliferation gains here.”

The issue of Pakistan’s nuclear programme was raised at a briefing at the White House as well where an Indian reporter asked spokesman Tony Snow how does Pakistan’s refusal to let US access Dr A. Q. Khan reflect on Islamabad’s commitment to fighting terrorism.