Episcopal Bishop John T. Walker was arrested outside the South African Embassy here yesterday, along with 77 other apartheid protesters, about half of them Episcopal priests.

Walker, bishop of the Washington diocese who was nominated earlier this week to be presiding bishop of the national Episcopal church, said he was making the "symbolic gesture" because "I feel compelled by the God I worship to do so," and in support of South African Bishop Desmond Tutu, a longtime friend.

Yesterday's arrests brought to 1,503 the number of persons arrested since the daily protests began 17 weeks ago.

Black South Africans, "though created in the image of God, are treated as things and animals by other Christians" in that country, Walker said. He added that in a recent visit to that country he saw "children, women and men . . . who live far less well than do the dogs, cats and cattle of the Free World."

The bishop, who is black, sent a pastoral letter last week to the more than 100 parishes of the Washington diocese saying he was planning to protest and invited fellow Episcopalians to join him. More than 300 turned out to march and chant antiapartheid slogans, accompanied by honking and thumbs up salutes from sympathetic motorists passing on busy Massachusetts Avenue.

Randall Robinson, coordinator of the protests that have spread to 23 other American cities, said yesterday's turnout was considerably larger than usual.

Walker told the gathering of generally well-dressed protesters, about half of them white, that he was "deeply moved by the turnout." They in turn cheered and applauded his assertion that "my ministry . . . in the church of God demands that I show my love for the oppressed peoples of the world in some concrete, although in this case, symbolic, action."

At the annual diocesan convention in January, Walker apologized for not having been arrested at the embassy. He said he had applied for a South African visa to attend Tutu's installation as Anglican bishop of Johannesburg, and had been advised that he wouldn't get the visa if he took part in the protest.

"I promise you that if the demonstrations are still going on, I'll get arrested when I return," he told the Jan. 19 convention.

People from a wide range of religions have swelled the ranks of the protests. "Religious institutions generally have contributed from 30 to 40 percent of the pickets," said David Scott, one of the protest coordinators.

Protesters have included top leaders of liberal mainline Protestant bodies -- the National Council of Churches, United Methodists, United Presbyterians, United Church of Christ, the American Friends Service Committee and some Lutheran groups -- as well as grass-roots clerics and lay members.

Area black churches have also been deeply involved, and on Christmas Day, a Jewish group took over so Christians could celebrate their holiday.

But Walker acknowledged yesterday that progress has been slow, and added, "But this we know: It will not come about through silence or inaction."