WASHINGTON--In one of the largest anti-war demonstrations held in Washington since the end of America's involvement in Vietnam, tens of the Pentagon to protest U.S. military aid to El Salvador and proposed cuts in federally funded social programs.

Arriving in buses from cities across the country, the demonstrators sang, chanted and waved multi-colored banners as they listened to speakers denounce American invetervention abroad and the injustices of capitalism at home.

Several March organizers said that more than 100,000 people eventually gathered at the Pentagon, but an Associated Press report said that, according to Pentagon security officers, the crowd numbered about 25,000.

Those who attended the rally--including 35 from Harvard and about 1300 from Boston--hailed it as the renewal of the anti-war movement of the late 1960s and early 1970s. They also praised the inclusion of many groups that did not participate in the protests of the Vietnam War years.

Broad Coalition

Labor union members, welfare recipients, and gay and lesbian activists joined representatives of urban Black communities, church groups and traditional anti-war organizations in demanding an end to the oppression they linked to increased defense spending and lack of concern for the poor.

As screaming protesters punched the air with closed-first salutes, March organizer Laurie Fierstein pointed at the Pentagon and said, "You can't above your program of war, racism and cutbacks down the throats of the people."

As screaming protesters punched the air with close-first salutes, March organizer Laurie Fierstein pointed at the Pentagon and said. "You can't shove your program of war, racism and cutbacks down the throats of the people."

"there's a great need for a militant people's movement." Flerstein added, predicting that the coalition organized for yesterday's march would grow and "prepare for future struggles."

Speakers representing Black and gaylesbian groups praised their followers' courage for joining the anti-war movement and compared the Reagan administration to the Ku Klux Klan, the Nazi Party and the Moral Majority.

"The present direction of this country is madness." The Rev. Herbert Daughtry, chairman of the National Black United Front, said, drawing repeated ovations from the crowd.

Crowd Fermation

Activists from as far away as Texas began congregating at 8:30 a.m. on an open field between the Lincoln Memorial and the State Department.

After four-and-a-half hours of picnicking and speech-making in a carnival-like atmosphere, the individual groups felt into a tightly organized line and marched up 22nd St. toward the C St. entrance of the State Department.

Chanting "No draft, no war. U.S. out of El Salvador." the demonstrators circled back toward the Lincoln Memorial and walked slowly across Memorial Bridge to the grassy slope facing the north side of the Pentagon.

A large squad of official guides provided by the Peoples' Anti-war Mobilization (PAM)--the coalition of groups that organized the event--kept marchers within the area marked off for them, and there were no confrontations with police.

Rival Rally

As the mile-long mass of demonstrators snaked its way into Vircinia in a procession that lasted about two hours, members of the Marxist Spartacus League tried to initiate a separate rally along the Potomac, about 500 yards away from the edge of the main gathering.

The Spartacists challenged marchers to "take a stand and support the leftists in El Salvador's bloody civil way."

Hundreds of marchers stopped near the Spartacists' sound truck, but almost all of them headed for the concession stands and portable toilets situated nearby.

At least five unrelated Marxist groups completed for demonstrators' attention and sold copies of their parties' newspapers throughout the rally.

Several non-Marxist groups had expressed dissatisfaction last week with what they called "the unfair domination" of the Worker's World Party (WWP) in the leadership of PAM, but no tension was apparent during the demonstration yesterday.

The WWP first suggested a May 3 anti-war march and began forming PAM in January.

A potential clash between the anti-war protesters and demonstrators supporting U.S. policies toward El Salvador was avoided by policy officials who scheduled the two rallies at different times and in different parts of the Capitol.

Others who spoke at the Pentagon between performances by several musical groups included women's rights leader and former New York Rep. Bella Abzug. Larry Holmes, head of the WWP and a ranking member of PAM. and a spokesman for El Salvador's leftist Democratic Revolutionary Front (FDR).

Yesterday's rally was "the greatest show of solidarity with the people of El Salvador." the FDR spokesman said.

Similar demonstrations were held yesterday in Denver and San Francisco for those who could not make the trip to Washington from the West Coast