ISLAMABAD, Pakistan (AP) _ When the U.S. Defense Secretary arrives this week, he'll find a country fiercely committed to its nuclear program despite Washington's attempts to halt a regional arms buildup.

The United States cut aid to Pakistan in 1990 over the nuclear issue, but the sanction has made Pakistan even more reliant on its nuclear weapons program, according to analysts.

The political and military leaders of this Muslim country firmly believe the nuclear bomb is their best defense against neighboring India, which is much larger.

``So long as India maintains its nuclear capability and continues to be a serious threat to Pakistan's security, Pakistan will keep its nuclear capability,'' said Zafar Iqbal Cheema, professor of defense studies at Quaid-e-Azam University in Islamabad.

The South Asian rivals have fought three wars in the past half-century, and many fear a future confrontation could quickly escalate into a nuclear exchange.

Neither country has joined the Nuclear Non-Proliferation Treaty.

So popular is Pakistan's nuclear program that it's considered political suicide even to whisper about concessions. The military remains Pakistan's most powerful institution and it considers the nuclear program sacred.

Prime Minister Benazir Bhutto says her country is capable of making an atomic bomb, but has not done so. U.S. officials say Pakistan has all the components necessary to assemble a bomb on short notice _ perhaps within hours.

Muslim fundamentalists marched last week to protest Perry's visit, calling it America's latest attempt to dismantle Pakistan's nuclear program.

Meanwhile, Pakistani Defense Secretary Salim Abbas Jilani said his country had stepped up its domestic arms production since the U.S. halted aid and stopped selling military equipment to Pakistan at bargain prices.

Military spending already accounts for about half of Pakistan's $13 billion annual budget.

Pakistan expects to produce its own tanks by 1997. It already makes missiles, though they are not believed to be able to deliver nuclear weapons.

Washington says Pakistan also bought M-11 missiles _ capable of carrying nuclear warheads _ from China. Both countries deny the sale.

The French have agreed to sell Pakistan three submarines as well as the know-how to build them.

The U.S. aid cutoff has blocked delivery of 71 F-16 fighter jets that Pakistan purchased from the United States several years ago. Pakistan is now trying to get back its $650 million from the United States so it can shop elsewhere.