NEW DELHI, DEC. 20 -- India and Pakistan have agreed to implement a treaty banning attacks on each other's nuclear facilities, according to the United News of India and other reports.

The agreement, although viewed as modest, would mark the first significant step back from confrontation since tensions over the disputed state of Kashmir led both countries to rush troops, warplanes and artillery to their border earlier this year. Indian and Pakistani armed forces have remained face to face in a state of readiness since then.

Indian Foreign Secretary Muchkund Dubey and his Pakistani counterpart, Sheharya Khan, agreed following a round of talks in Islamabad, Pakistan's capital, that treaty documents would formally be exchanged and the accord's provisions implemented next month, more than two years after the treaty was signed, UNI said.

The talks between Dubey and Khan, the third round in a series aimed at reducing tensions, also reportedly produced agreements to resume weekly military-to-military contacts and to finalize a proposal for advance notification of military exercises.

The treaty banning strikes on nuclear installations was first proposed five years ago and was signed in December 1988 by former Indian prime minister Rajiv Gandhi and former Pakistani prime minister Benazir Bhutto. Both countries later ratified the agreement but it was never put into effect.

Indian officials attributed the delay to Pakistan's refusal to provide a list of nuclear facilities to be covered by the ban, fueling fears in India that Pakistan was conducting military nuclear research at secret locations. It was not immediately clear whether Pakistan would provide such a list when treaty documents are exchanged.

Khan today reiterated Pakistan's desire for a nuclear nonproliferation agreement with India, and he cited a recent treaty between Brazil and Argentina forswearing development of nuclear weapons as a model. India, however, has consistently rejected any regional nuclear ban unless China and possibly Israel are included.

Unlike the agreement between Brazil and Argentina, the treaty between India and Pakistan would not ban nuclear arsenals. Instead, it would provide a shield behind which each country could develop atomic weapons free from preemptive attacks. At the height of tensions over Kashmir last spring, there were fears here and abroad that India might start a war by attempting to knock out Pakistan's nascent nuclear capabilities.

India tested a nuclear explosive in 1974 and is believed to be capable of deploying nuclear weapons within weeks if a war with Pakistan were to erupt. Pakistan has been working assiduously since the 1980s to match India's nuclear capability, according to Western intelligence officials, although Islamabad maintains that its nuclear program has only peaceful aims.

In October, the United States suspended $560 million in annual economic and military assistance to Pakistan because of concerns that Islamabad may be close to possessing a nuclear bomb. U.S. fears about nuclear proliferation in South Asia intensified this year after an uprising by Moslems in Kashmir produced threats of war in Islamabad and New Delhi.

The threats have died down recently, cooled by superpower lobbying and domestic instability on both sides. But neither country has pulled back its military forces. Tensions continue to be stoked by Pakistan's covert assistance to Kashmiri guerrillas and India's recent spate of bloody street battles between Hindus and Moslems.

Earlier this year, two rounds of talks at the foreign secretary level failed to produce any significant agreement to reduce border tensions. Dubey and Khan attributed their modest success this week to clear marching orders from their countries' new prime ministers, socialist Chandra Shekhar in New Delhi and rightist Nawaz Sharif in Islamabad.

The new leaders met for the first time at a regional conference in the Maldives in November and said they would attempt to put bilateral talks back on track. Another round of discussions is scheduled for February.