WASHINGTON, Oct. 21 —The United States and the Soviet Union are exerting strong diplomatic pressure on India to avoid any action that might lead to hostilities with Pakistan, American officials said here today.

The latest reports from Moscow are said to reflect guarded optimism that the Indian Government is heeding Soviet, American and other appeals for restraint.

The Soviet Government is also reported to have warned the United States, however, that it fears that Pakistan may move first against India. Moscow is said to be calling on the Nixon Administration to exert its own influence on President Agile Mohammad Yahya Khan to avoid provocation or hostilities on either the West Pakistan-India border or on the East Pakistan‐India border. The two parts of Pakistan are separated by 1,000 miles of Indian territory.

Thant Offers Mediation

The United States is understood to be prepared, if asked, to support a new offer to India and Pakistan by Secretary General Thant, placing the United Nations at their disposal for mediation purposes. Mr. Thant is said to have circulated his offer to each member nation in the Security Council.

Two recent developments have perturbed senior officials far more than the Administration has publicly indicated.

Yesterday, for instance, there were fresh reports from New Delhi that Prime Minister Indira Gandhi might cancel her projected visit, starting Sunday, to Britain, France, Austria, Belgium and the United States—where she is due Nov. 3 for five days.

Troop Moves Reported

“If she cancels her trip it will look really bad,” a ranking official remarked. “But if she does leave India it would seem unlikely that the Indian Army would launch an attack in her absence.”

Diplomatic sources reported today that. Mrs. Gandhi was still planning to adhere to her travel schedule.

The second disturbing development has been the widespread deployment of Indian troops in the last week. Indian forces are now reported to have virtually encircled East Pakistan, where West Pakistani troops are repressing a Bengali independence movement.

Meanwhile, Pakistani troops in West Pakistan are also being moved up along the Indian border and the Pakistan Air Force has begun recalling pilots from a training mission in Saudi Arabia. Reports here say Pakistan has placed her air force on a state of alert.

The latest increase in tension comes six years after a 22‐day Indian‐Pakistani war, which began Aug. 5, 1965. On Jan. 10, 1966, thanks largely to mediation efforts by Premier Aleksei N. Kosygin of the Soviet Union, President Mohammad Ayub Khan of Pakistan and Lal Bahadur Shastri, Prime Minister of India, agreed at Tashkent in the Soviet Union, to withdraw their forces to positions held before the fighting.

The 70,000 West Pakistani ground forces in East Pakistan, qualified informants here say, are largely tied up combating the steadily increasing forays of the militants supporting Bangla Desh—the insurgents name for a Bengali nation independent of West Pakistan's authority.

The West Pakistani Army was ordered into action last March 25 by President Yahya Khan. The 70 million East Pakistanis, most of whom are Bengalis, are Moslems like the West Pakistanis but are different ethnically, linguistically and culturally.

Indian Army concentrations south of Sikkim have led to speculation among military experts here that the Indian Army is preparing to resist any possible Chinese counterpressures designed to relieve the Pakistani forces in East Pakistan in the event of hostilities.

“The monsoons are ending and there are about four to five weeks before snow fills the passes in the Himalayas and hampers movement,” said one area specialist. “It looks as if the Indians are getting prepared for anything that might happen —although there are no indications the Chinese are moving up troops in Tibet or Sinkiang.”

Other sources suggested that China's domestic political problems—the extent of which is still unclear—plus the current visit of Henry A. Kissinger, President Nixon's national security assistant, might act to restrain any overt Chinese action against India.