A U.S. military surveillance plane and a Soviet jet fighter came within 15 feet of colliding over the Sea of Japan this week, according to Defense Department sources.

A Navy P3 Orion equipped with special electronics for intelligence-gathering was on patrol when a MiG23 drew near, according to one source.

Another source said the two aircraft were "playing games" when the near-collision occurred. No injuries were reported.

Although U.S. and Soviet military planes frequently buzz or chase each other while maneuvering in international airspace, the planes usually do not come so close to colliding, the sources said.

Sources said the planes were over international waters when the incident occurred.

The Orion is one of 12 P3s that the military has converted for sensitive intelligence-gathering missions.

Designated the EP3 for electronics warfare, the planes are equipped with sophisticated communications instruments that can intercept and analyze radio and satellite sig- nals.

The Navy uses most of the P3s for surveillance of surface ships and monitoring submarine movements. They are equipped with defensive weapons against land and sea targets but not with air-to-air mis- siles.

U.S. fighters are scrambled routinely to monitor Soviet bombers and surveillance planes that ply the skies over international waters off Alaska in the Pacific and Greenland and Iceland in the North Atlantic.

The confrontations are seldom hostile, with pilots from both sides frequently using the opportunity to photograph the other's aircraft.

The planes sometimes draw near enough for crews of one craft to see their opposites displaying magazine photographs -- usually of scantily clad women -- according to pilots who have flown the missions.