ISLAMABAD, PAKISTAN, OCT. 12 -- Pakistani Prime Minister Mohammed Khan Junejo has ruled out any further assurances to the United States on its nuclear program as a way to overcome obstacles to continued U.S. assistance to this strategically placed South Asian nation.

"We gave commitments at an earlier stage and as an elected government I will only go further" to the extent that India, Pakistan's neighbor and archrival, also is included, the prime minister said in an interview yesterday.

His comments underscored the defiant mood in this country to the U.S. law that links aid to nuclear nonproliferation.

"It must be made clear that Pakistan can't be singled out on this issue," Junejo said.

The United States has suspended its $4 billion six-year aid program to Pakistan because of a procedural tangle in Congress and Pakistani nuclear developments. Washington now faces longer-term decisions on whether to revise its approach to nuclear nonproliferation laws or risk a break with Pakistan by cutting assistance.

The administration and some congressmen argue that the future of the Afghan resistance war against Soviet troops would be jeopardized by an aid cut because the military supply effort to the Afghan rebels is widely assumed to be implemented through Pakistan.

Junejo insisted in the interview, however, that Pakistan's policy on Afghanistan is a separate issue from the U.S. aid program.

In the interview, the prime minister also:

Spoke warmly of the changed Soviet attitude toward Pakistan and toward ending the eight-year Afghan war.

Said Pakistan was in contact with a key figure in a controversial case involving alleged Pakistani attempts to buy nuclear-related materials in the United States, but that his version of events could not be revealed until Pakistan had received key documents from Washington.

Suggested India was behind Pakistan's current troubles with the United States over the nuclear issue.

Acknowledged that recent bombings in Pakistan have created new pressure on his government to place restrictions on the 3 million Afghan refugees now living in Pakistan.

The nuclear issue has placed an unusual strain on relations between the United States and Pakistan in recent months after years of growing ties following the Soviet invasion of Afghanistan. Pakistan's nuclear program has been an issue of contention throughout the period, however, since U.S. law prohibits assistance to a country found to be developing nuclear weapons.

In the past, Pakistani officials have given assurances that they are not developing a weapon and the Reagan administration has consistently waived the aid restriction. But new controversy arose recently following leaks of U.S. assessments of Islamabad's program, statements by top Pakistani scientists, and the arrest of a Pakistani national in Philadelphia this summer on federal charges of trying to buy a type of steel widely used in nuclear programs.

Pakistan is believed to have developed most or all of the components of a nuclear device but not to have assembled one. India exploded a nuclear device in 1974. Both countries maintain that their nuclear programs are only for peaceful purposes.

Pakistan has endorsed, but India has rejected, a U.S. proposal for a treaty between the two countries banning nuclear weapons.

Junejo said he had investigated the Philadelphia case involving Arshad Pervez, the arrested Pakistani national, and concluded that "Pakistan had no hand in it at all." He said the steel "which was to be exported to Pakistan . . . could be had from other countries. Why should I go to the United States and create a problem for myself? Common sense says we would not go and create an issue when we are already under a difficult situation."

As a result, Junejo said he and his advisers believe that India was behind a plan to disrupt U.S. aid to Islamabad. Indian officials have denied any involvement.

Junejo said his government knows the whereabouts of a former brigadier general in the Pakistani Army, Inam ul-Haq, who is widely believed to have been Pervez's contact in Pakistan. But, he said, he would not reveal ul-Haq's version of events until he received documents on the case requested two months ago from the United States.

U.S. officials are believed to be eager to question the brigadier general because he is believed to be central to determining whether the Pakistani government was involved in the Pervez case.

Junejo said ultimately that Pakistan could survive a U.S. aid cut. "We hope we will succeed, but if it is going to be otherwise, we have to draw a new line," he said. "That new line means {we need} to generate our own good resources . . . we have the capability to meet our requirements."

Even if aid were cut off, Junejo said, Pakistan's policy toward Afghanistan would not change.

"There was no U.S. aid to Pakistan in 1979 when the Afghans first came," he said. "We will pursue our policy on Afghanistan. That is very clear."

Nevertheless, Junejo spoke warmly of Moscow's attitude under Gorbachev. He indicated Pakistan's desire to continue developing ties with the Soviet Union as a key to solving the Afghan problem and perhaps other regional issues. Moscow enjoys close relations with India as well.

"After the arrival of Mr. Gorbachev, they have taken a practical approach toward the whole problem," Junejo said, noting the direct talks that have been held between Pakistani and Soviet diplomats in recent months. A new round of talks is expected, he said.

On the issue of Afghan refugees, Junejo said that between 5,000 and 10,000 Afghan refugees were continuing to enter Pakistan every month, adding to the more than 3 million already believed to be in the country. He said he would like to confine them to refugee camps.

"Every time there is a bomb blast the refugees get blamed," he said. "So it is for their own good for them not to be seen in the center of the local population."