The daily antiapartheid demonstrations and arrests at the South African Embassy, which began last Thanksgiving Eve, are ending and a new campaign aimed at pressuring American corporations to shut down business operations in the racially segregated country will be launched soon, protest leaders said yesterday after a rally marking the movement's first anniversary.

Embassy protests will continue intermittently, organizers said, but the focus of the antiapartheid campaign will be shifted to those firms that help support South Africa's economy.

The Rev. Jesse Jackson, Coretta Scott King, Mayor Marion Barry and United Mine Workers of America President Richard Trumka were among the estimated 600 persons who marched in the afternoon rain to the embassy on Massachusetts Avenue NW.

Ten persons, including National Organization for Women President Eleanor Smeal, were arrested there yesterday, bringing the total arrest figure at the embassy since last Thanksgiving eve to 2,918, D.C. police said.

The rain and the comparatively small turnout -- about 5,000 persons joined an Aug. 12 march to the State Department -- did not seem to dampen the spirits of the demonstrators.

"If you think it's a nasty day out here today, just think about what a nasty day it is every day in South Africa," said former tennis star Arthur Ashe, a founder of Artists and Athletes Against Apartheid.

Jackson applauded expanding the antiapartheid campaign into the economic arena and said consumer boycotts are necessary to offset the support South Africa is getting from western governments, particularly the United States and Great Britain.

"Apartheid could not survive on the strength of [South African President Pieter W.] Botha," Jackson told reporters shortly before demonstrators set off from 23rd and P streets NW for a rally a block south of the embassy. He said the system is being bolstered "by the Reagan-Thatcher-Botha sleaze friendship."

King, widow of slain civil rights leader Martin Luther King Jr., said she and three of her children had been arrested at the embassy to protest apartheid and would gladly undergo the action again.

"We're going to lobby as long as it's necessary, we're going to go to jail as long as it's necessary," she said. "The world is watching America, and we are the only people who can change the policies of our government."

Demonstrators chanted for the release of jailed South African opposition leader Nelson Mandela, and speakers praised the nonviolent leadership of Nobel laureate Bishop Desmond Tutu.

Randall Robinson, a leader of the Free South Africa Movement's steering committee, announced that Tutu will come to the United States Jan. 8 to accept a "Freedom Letter" signed by a million Americans. The presentation, Robinson said, will take place near the embassy.

In ending the daily protests at the embassy, organizers tried to put the best face on their decision halt a protest campaign that has done much to call attention to apartheid policies. But they conceded that arranging daily arrests had become a drain on staff time, especially in recent months as the number of arrests and pickets dwindled.

In addition, media attention to the embassy protests had declined, and organizers said they were eager to devote their energies to promoting economic boycotts and congressional lobbying.

"If we're not at the embassy, it's because we're someplace else," Robinson said.

Cecelie Counts, the antiapartheid group's protest coordinator throughout, said a lot of work will be necessary to organize planned picketing and boycotts of financial, computer, fuel and import firms that do business in South Africa.

But she said she expects the support will be there for such new protest targets.

"We started with three people inside [the embassy] and 20 people standing outside," she said. "We hoped we could sustain this movement for a week -- I think this is now the 54th week."