The Indian Ocean, where President Carter seeks "mutual military restraint" by agreement with the Soviet Union, is the world's third largest body of water and, increasingly, the focus of international attention.

Since 1968, when the British announced their intention to withdraw from the Indian Ocean, claims of a "power vacuum" in the area have accompanied stepped-up maneuvering by the United States, the Soviet Union and other nations.

The United States is building an air-naval base on the tiny mid-ocean island of Diego Garcia in order to project a presence in the area. The Soviet Union is constructing air and naval facilities at Berbera on the coast of Somalia, an east coast African state. Both the United States and Russia, along with the French and other powers, have sent naval task forces to the area periodically.

Last Wednesday, Carter told a news conference that he has asked the Soviet Union to agree to "complete demilitarization" of the Indian Ocean. In New York yesterdy, an administration official traveling with Carter said the U.S. aim is a reduction or perhaps an elimination of forces in the area.

The National Security Council has not hammered out a formal U.S. position on Indian Ocean demilitarization, which in the past has been strongly opposed by the Navy and other elements of the executive branch. If the Soviet Union shows interest in the Carter plan, a major bureaucratic struggle involving the Pentagon is considered likely.

In December, 1971, the U.N. General Assembly adopted to a resolution sponsored by Sri Lanka to declare the Indian Ocean a zone of peace. That resolution and similar U.N. General Assembly resolutions in the following three years called on the great powers to begin consultation with states bordering the ocean to end military escalation and eliminate all bases from the region.

The Soviet Union has made statements at times in favor of demilitarization of the Indian Ocean. However, it claims that the facility in Somalia belongs to that country and thus is not a Soviet base.

According to a forthcoming study by Dale R. Tahtinen of American Enterprise Institute, the Soviet Union's Indian Ocean squadron generally consists of cruisers, destroyers, destroyer escorts and attack submarines, sometimes argumentated by a helicopter carrier.

In January, the United States for the first time dispatched a nuclear-powered task force for maneuvers in the area. The ships, including the aircraft carrier Enterprise, were employed as a show of force off the African coast when Ugandan President Idi Amin seemed to threaten U.S. residents there. According to the Pentagon, the U.S. fleet had made 12 previous voyages into the Indian Ocean since the 1972 India-Pakistan war.