Moving in a solemn line with drums beating a steady cadence, more than 2,000 American Indians and supporters marched into the nation's capital yesterday - the final seven miles of their cross-country Longest Walk for prayer, politics and preservation.

Children and men, clan mothers and tribal faith keepers in an assortment of feathers and blue jeans trudged through the muggy heat, led by their spiritual elders.

Shepherded by police and Indian security guards, the cavalvade came down Georgia and Arkansas avenues and 16th Street NW into Meridian Hill Park (also known as Malcolm X Park) for a midday rally before moving past the White House to the Washington Monument grounds.

"Welcome to Indian country," shouted Longest Walk leader Bill Means to a cheering crowd of blacks, whites and reds that had grown to 3,000 in Meridian Hill Park.

"We all have the same goal - we're fighting for our survival," said Ernie peters, spiritual leader of the walk.

Speaker after speaker ranging from comedian Dick Gregory and various Indian leaders to movie star marlon Brando and a representative of the Puerto Rican Socialist Party brought the same message: privileged whites stole America from the Indians and are now despoiling it; control of the land must be taken from the despoilers and returned to ordinary people before all humanity dies.

Clyde Bellecourt, a walk coordinator and leader of the militant American Indian Movement, reminded the crowd that the Indians have come to Washington to protest legislation in Congress that would abrogate all U.S. treaties with Indians and make vast areas held by the government in trust for the Indians more easily available to private development.

"The multinational corporations want our land," he said, "and the name of the game is energy . . . They want uranium, coal, Lignite that's under our land . . . The theft took place 150 years ago of our farmlands and timber is no different from today."

The march and rally yesterday marked the beginning of eight days of demonstrations, protests, religious ceremonies and educational workshops planned by the Indians.

Most of the participants are encamped at Greenbelt Park in Prince George's County, 12 miles from downtown Washington, and are to come into the city each day this week for rallies and marches to Congress, the White House, Supreme Court and the FBI building.

At the same time, 200 to 300 religious leaders are expected to maintain a four-day vigil at an enclosed "spiritual camp" with tepees and a sacred altar in West Potomac Park near Lincoln Memorial.

Leaders repeatedly stressed the twofold purpose of their week-long actions here: to protest specific legislation, which they say would abolish various land, fishing, mineral and other Indian treaty rights and also to educate non-Indian America about their culture and spiritual life.

The march into Washington yesterday completes the five-month long 2,700-mile Longest Walk that started Feb. 11 from Sacramento, Calif., and gradually, gathered followers as it progressed eastward. Hundreds of participants from dozens of tribes walked portions of the trek along U.S. 50 and Interstare 70, and a handful - perhaps a dozen - made the entire walk.

The marchers entered the District of Columbia yesterday on Georgia Avenue after walking through Silver Spring in suburban Maryland and were greeted at the D.C. line by City Council members Douglas Moore (D-At Large) and Hilda Mason (Statehood-At Large) and by Rep. Ron Dellums (D-Calif.), a longtime suporter of Indian causes.

Marie Nahikian, an at-large City Council candidate who says she is part Armenian and part Seminole Indian, joined the march line along with several hundred other Longest Walk supporters who had gathered at the D.C. line.

The procession moved south along Georgia Avenue with Peters at the lead holding a sacred pipe wrapped in a blanket. News photographers and bystanders with cameras were thrown into confusion when Indian security guards snapped order at them not to take pictures of the pipe while it was being carried. The pipe is considered a sacred object and is not supposed to be photographed, but the security guards in their haste often did not explain that.

Behind Peters and the other spiritual leaders marched about 1,000 Indians - men, women and children, some dressed in traditional garb, some in modern style. For most part, they marched in silence.

Behind the Indians came another 1,000 support demonstrators, most of them white many of them activists in the Clamshell Alliance and other anti-nuclear organizations that have formed a loose political bond with the Indians on the issue of land and resource preservation.

Heading the support demonstrators was a band of Japanese Buddhist and shaved heads, chanting and playing small hand drums. Their leader, 93-year-old Fuji Guruji, was pushed along in a wheel chair and peered brightly at the crowds aroung him.

When the marchers assembled in Meridian Hill Park six miles and two hours after entering the District of Columbia, Philip Deere, a Cree Indian and religious leader, opened the rally with a prayer, much of it in his native tongue.

Oren Lyons, a chief in the Six Nations Iroquois Confederacy of upstate New York, said the threat to Indian life "goes beyond racism" and is jeopardized now along with all humanity by industrial waste and pollution.

"We are here to see that the eagle, the bear and the wolf will survive and that our great-grandchildren will see the green trees around them."

Comedian Gregory also condemned rampant pollution and the economic priorities of the U.S. government.

"We've got the greatest military machinery on this planet," he said, "and while we spend all this time telling the Russians we can whup 'em and they tell us they can whup us, there's grasshoppers out there eating up two states."

Brando, who like Gregory had joined the march earlier in the day, told the crowd: "I am astonished that the secretary of State, the president of the United States and the vice president are now going around the world and have the nerve to be talking about human rights when we're the very last nation on earth to give up our colonial control of a people."

City Councilman Moore, dressed in flowing African robes, equated black problems with Indian problems and said a current effort by white business and political interests to force blacks out of this majority black city is similar to congressional efforts to push Indians off their land.

The crowd at Meridian Hill Park and later at the Washington Monument grounds covered a broad spectrum of races and ages.

Some said they were there to support the Indian cause, some said they admired the Indian way of life, some said they were simply curious.

"I'd given up hope; I thought people didn't care," said Karla Button, 23, a Senaca Indian from New York. "Seeing the level of support (at Meridian Hill Park) made me feel really good. It made me feel really proud."

Peggy Leftwich, 60, a Washington resident who said she is part Cherokee, part Navajo and part black American, said she felt "close to the Indians. They've been mistreated and haven't been given their rights, and a lot has been taken from them."

Fr. John Garvey, a priest in a rural South Dakota parish, said he came "to cry a little bit." But the tears spring from happiness, he said. "They're finally getting some recognition."