The Rev. Carl McIntire, the New Jersey evangelist who has led numerous demonstrations here in support of the United States military, told 300 flag-waving, hymn-singing followers at the Washington Monument yesterday that next Saturday's March on Washington is a front for international communism.

"What they do next Saturday will help the communists take over the world," McIntire said to light applause from his seated audience, which had marched 1.5 miles up Pennsylvania Avenue in yesterday's sweltering 101-degree heat.

Organizers for the March on Washington, however, denied McIntire's allegations yesterday afternoon. Donna Brazile, the march's national mobilization director, said McIntire's charge is a result of "paranoia," and that communists play no role in organizing the march. "Everything that's right and progressive in this country is eventually called pro-communist by somebody," she said.

McIntire, 77, who heads a congregation in Collingswood, N.J., said he bases his conclusion on the fact that some of the organizers of this week's march are active in the nuclear freeze movement. He and his supporters said they believe the nuclear freeze movement is controlled by communist agents. McIntire added in a speech that the civil rights marchers' slogan of "Jobs, Peace and Freedom" is simply "the cover they have for the communist peace offensive."

McIntire's followers, almost all of whom were white, also distributed leaflets saying that Saturday's march, 20 years after the historic civil rights march on Washington led by the Rev. Dr. Martin Luther King Jr., must be communist-inspired because the American Communist Party's newspaper, the Daily World, has promoted it.

According to a show of hands of the ralliers, most of them were from Maryland, New Jersey and Pennsylvania. Yesterday's gathering was, like many others organized by McIntire, a chance for anti-communist Christians to meet, sing songs like "Onward Christian Soldiers," and exchange ideas about what they say is a growing communist menace.

According to some of them, gun control proponents, the nuclear freeze movement, the Internal Revenue Service, the Federal Communications Commission, most newspapers and television stations and Satan are all involved in a plot to stifle freedom and promote communism.

McIntire, a tall man who kept his gray suitcoat on throughout the day despite the heat, led the marchers from their gathering point at Fourth Street NW and the Mall carrying a sign saying "De-Ice the Freeze." Other marchers carried signs saying "Freeze Now, Fry Later," and "Disarm and Be Six Feet Under."