MOSCOW (AP) _ Soviet gunners disguised as Egyptian soldiers shot down 21 Israeli fighter jets in the summer of 1970 during Egyptian-Israeli combat near the Suez Canal, a Soviet newspaper reports.

The Soviets openly assisted the Egyptian army until a 1971 break in Soviet- Egyptian relations, but neither country had formally revealed that the Soviets engaged in direct combat with Israeli warplanes.

The Sovietskaya Rossiya newspaper quoted a retired Soviet colonel, Konstantin Popov, as saying divisions of Soviet anti-aircraft gunners were involved in the combat, bringing down Israeli Mirage and Phantom fighters.

It said Popov commanded one of the divisions near Suez and recalled the fights with Israeli planes in detail in a full-page article.

The officially Soviet press, which has been reporting on previously censored chapters of the Soviet military's past, carried a similar revelation last year about the combat role of Soviet ''advisers'' in the Vietnam War.

Popov described how Soviet soldiers in civilian dress were smuggled on a merchant ship from the Black Sea into the Mediterranean, past corrupt Turkish guards, and then transported to Egypt.

On June 30, 1970, a Soviet division brought down its first Phantom, Popov was quoted as saying. On July 18, eight Soviet troops were killed when they were hit by Israeli planes.

''In all, during the military activity of the Soviet pilots and gunners, 21 Israeli planes were brought down,'' Sovietskaya Rossiya said.

Popov credited the Soviet gunners with stopping Israeli air attacks on Egypt. They ''forced the Israelis to understand that Soviet gunners would not allow them to act freely in the skies over Egypt and heighten aggression,'' the article said.

Popov was unimpressed, however, by the reward he said the government of Egypt gave the Soviet troops on their departure: some hastily stamped aluminum medals.