More than a dozen community leaders and political activists held two news conferences yesterday to denounce Saturday's planned rally by the Ku Klux Klan and give details of counterdemonstrations to be held that same day.

Civic leaders ranging from Mayor Marion Barry and D.C. Del. Walter E. Fauntroy to James Mihalik, chairman of the Montgomery County Human Relations Commission, called for countering the Klan by such activities as visiting prisoners and feeding the poor.

The All Peoples Congress, a coalition of left-of-center community activist groups, promised 60 busloads of demonstrators to protest "the Klan, their big business backers and the Reaganites."

The outpouring of anti-Klan rhetoric came four days before some 200 Klansmen from around the country are scheduled to gather at the Capitol and march down Pennsylvania Avenue to the White House, in the first such demonstration here by the organization in 58 years.

"We will answer the Klan's discordant sounds of hate with a symphony of acts of love for our neighbors," said Fauntroy, at a press conference at the Rayburn House Office Building, flanked by a dozen community leaders who have formed the ad hoc Coalition for Community Unity.

While the Klan marches and rallies at Lafayette Square, more than 30 churches will serve free noontime meals to the hungry and many churches will gather clothing and food baskets for the destitute, said the Rev. Ernest R. Gibson, executive director of the Council of Churches of Greater Washington. Twenty participating churches will simultaneously distribute 30,000 pounds of surplus butter, he added.

Church volunteers will visit prisoners at the D.C. Jail and Lorton Reformatory, and the Greater Washington Board of Trade will assist in a job-counseling program for the unemployed, Gibson said.

Mayor Barry, in a brief appearance at the morning news conference, pledged the city's support for the coalition's "vision of a positive move" in response to the Klan.

Meanwhile, at a news conference at the Wilson Center in Adams-Morgan, the All Peoples Congress unveiled plans for what it promised would be a massive counterdemonstration in McPherson Square timed to coincide with the Klan rally a block away.

"We are planning a legal, orderly and spirited demonstration," said Monica Moorehead, national coordinator of the APC. "We will let them know we are here."

Ten speakers ranging from Josephine Butler of the D.C. Statehood Party to Tom Soto of the Peoples Antiwar Organization attempted to link the Klan with other issues ranging from the size of the defense budget to political repression in El Salvador.

"The Klan is only the tip of the iceberg," said Malik Edwards, director of the Malcolm X Center in Southeast. "We know all these things are connected."

"It would be ridiculous to focus just on the Klan and not talk about the mentality that gives rise to the Klan," said Lawrence Bell, president of the Black Student Union at the University of Maryland. "The most dangerous Klan member in this country lives in the White House."

President Reagan denounced the Klan during his 1980 campaign.

Meanwhile, in Tuscumbia, Ala., Stanley McCollum, director of the national office of the Knights of the Ku Klux Klan and an organizer of the Saturday march, declined substantive comment on the projected counterdemonstrations, saying they were "expected."

"But Ronald Reagan's not a member of the Klan," he said. "If he was we'd banish him for some of his stands."