Johannesburg — Exiled black-nationalist leader Oliver Tambo has sent word to backers inside South Africa to curb excesses of ``black-on-black'' violence, and seek widened unity among all those, black or white, committed to establishing nonracial majority rule. Specifically, the leader of the banned African National Congress (ANC) has conveyed his disapproval of so-called ``necklacing'' - a method of murder in which gasoline-soaked automobile tires are placed around a victim's shoulders and set on fire. The practice, which accompanied the upheaval that erupted in fall 1984, is most often carried out against alleged informers or government collaborators in black townships.
Mr. Tambo said such killings risked damaging the ANC's political case for heightened world political and economic pressure on Pretoria. But, he indicated that the ANC had no plans to issue an unequivocal, public condemnation of necklacing. He was apparently concerned that this would undermine the morale and unity of black antigovernment militants, and draw energy away from an ``armed struggle,'' which Tambo said remained central to hopes of unseating the present political system.
His remarks came in a closed-door meeting with more than 100 ANC sympathizers who had journeyed from South Africa for an international anti-apartheid conference in Zimbabwe. Details of Tambo's speech to the visitors came from two informed sources who were present at the Zimbabwe symposium. The meeting, which drew delegates from Western countries, South Africa, and ANC headquarters in Zambia, was held to publicly dramatize the issue of ``Children, Repression, and the Law in Apartheid South Africa.''
One of the key, unannounced, functions of the conference was to allow private discussions between senior ANC leaders and supporters from inside South Africa. At least eight top ANC officials held a series of informal contacts with small groups, culminating in Tambo's address to a meeting of all the South African delegates.
Tambo is understood to have said that the ANC, which has been banned inside South Africa since 1960, would stand firm on making participation in any negotiations contingent on a commitment that talks would deal with a ``transfer of power'' to a new government elected in a nonracial, one-person, one-vote ballot.
He added that ``armed struggle'' would end only when such negotiations were possible. There could, in the meantime, be no talks on ``reforming apartheid.'' The sources said Tambo also used his discussion with the South African delegates to emphasize the role for liberal whites in his vision of a ``post apartheid'' country.
He reportedly said one reason the ANC had repeatedly demanded it be legalized was to make bridge building with whites possible. And any South African white who opposes the present system should be seen as having taken a first step toward the ANC's own vision of nonracial, majority rule. He is also said to have stressed the need to end rivalry among black anti-Pretoria militants, a reference to tension between the ANC and black-consciousness activisits who reject the ANC's vision of a role for whites in overturning the current system.
Journalists in South Africa operate under official press restrictions.