Pakistan has expanded its nuclear weapons production capability rapidly", the Post quoted David Albright, president, Institute for Science and International Security, as saying. Albright said that based on accelerated production of plutonium and highly enriched uranium, Pakistan may now have an arsenal upto 110 weapons.

The non-government United States analyst said that while continuing to produce weapons-grade uranium at two sites, Islamabad has sharply increased its production of plutonium, enabling it to make lighter warheads for more mobile delivery system.

Pakistan's has developed a new missile Shaheen II, with a range of 1,500 miles that is about to go into operation deployment. The country has also developed nuclear capable land and air launched cruise missiles, the institute said in a new report.

"The Pakistanis have significantly accelerated production of uranium and plutonium for bombs and developed new weapons to deliver them. After years of approximate weapons parity, experts said, Pakistan has now edged ahead of India, its nuclear-armed rival," the Washington Post said.

The paper said while Pakistan has produced more nuclear-armed weapons, India is believed to have larger existing stockpiles of such fissile material for future weapons.

Dubbing Pakistan as one of the world's most unstable regions, the Post said an escalation of nuclear arms race in South Asia possess a dilemma for Barack Obama-led US administration.

It said in politically fragile Pakistan, the administration is caught between fears of proliferation or possible terrorist attempts to seize nuclear materials and Pakistani suspicions that the US aims to control or limit its weapons programme and favours India.

Quoting Pakistan's defence attache at its embassy in Washington, the report said the number of Pakistani nuclear weapons are heavily deployed near its border with India.

The paper said that in December 2008, Peter Lavoie, the United States national intelligence officer for South Asia, told North Atlantic Treaty Organisation officials that "despite pending economic catastrophe, Pakistan is producing nuclear weapons at a faster rate than in any other country in the world".