DURBAN, SOUTH AFRICA, JAN. 29 -- African National Congress leader Nelson Mandela and Zulu Chief Mangosuthu Buthelezi, meeting today for the first time in more than 30 years, issued a dramatic joint appeal for an immediate end to the bloody rivalry among their followers that has taken more than 5,000 lives in the last five years.

Appearing together at a press conference after a daylong meeting here, the two leaders agreed they had achieved a major breakthrough toward restoring peace in South Africa's faction-torn black community.

Buthelezi termed the meeting, attended by large delegations from both sides, "a complete success" and said that despite the many deep policy differences between the two men "there was no acrimony whatsoever" during their discussions. Mandela said that the problems that had kept the ANC and Buthelezi's Zulu-based Inkatha Freedom Party at loggerheads for the past 12 years had been "fully addressed" and discussed "in a very cordial spirit."

While it had been impossible for the two powerful black political organizations to reach agreement on all issues dividing them, Mandela said, "we can only hope that {a reduction in violence} will be the result of the breakthrough that we have arrived at today."

The parties said they have agreed to establish mechanisms to deal with future outbreaks of violence and "to desist from vilification of either of our organizations and leaders." Participants said Buthelezi began the meeting with a vehement complaint against ANC leaders for their public disparagement of him as a legitimate black national leader and suggested that the defense of his honor was a prime reason his supporters had resorted to violence.

A joint communique issued by the two sides pledged them to "political tolerance and freedom of political activity," and -- addressing a demand made explicitly by Buthelezi -- the ANC agreed that the Inkatha Freedom Party had "the right to exist" as a separate entity with its own policies and programs.

Mandela and Buthelezi also pledged to visit together the districts here in Natal province and in the black townships around Johannesburg that had suffered most from the factional violence and to use joint crisis committees already established in those areas to resolve conflicts as they emerge.

Members of both delegations said it is too early to say whether the meeting of the two black leaders and the decisions made today would be sufficient to end years of slaughter among their followers. But they agreed that the peace summit was essential to the process of winding down the violence.

Buthelezi had been pressing for just such a session since Mandela was released from 27 1/2 years in prison last February, apparently convinced that it was the only way to establish his claim as a national black leader beyond his Natal power base. Several earlier attempts to arrange a meeting failed, largely because of strong opposition from within the ANC, particularly its leadership in Natal.

The meeting began with sharply contrasting remarks by the two leaders -- Mandela calling for a new era of peaceful coexistence, while Buthelezi seemed to go out of his way to emphasize their many past and present differences. The Zulu leader reviewed in detail all the insults he said had been leveled at him by the ANC because he had opposed its doctrine of armed struggle against South Africa's white-minority regime and chose to work within the system as chief minister of the government-backed Kwazulu homeland. He accused the ANC of trying "to castrate" him politically, and he declared that armed struggle "will not win the day" in the fight for black political equity.

Buthelezi also accused the ANC of taking an "anarchistic approach" in demanding that an elected constituent assembly write a new power-sharing charter for the racially divided country and that a transitional government be empowered to enforce it. "There will not be a constituent assembly . . . followed by an interim government," he said defiantly. "Those things are not achievable in South Africa."

He said the ANC and Inkatha should discuss "alternative approaches" but was vague about these, except to suggest that different viewpoints might be tested by public opinion, apparently in some sort of ballot.