JOHANNESBURG, South Africa (AP) _ The African National Congress on Saturday postponed talks with the government on dismantling apartheid, saying that police shootings of black protesters have soured the negotiating climate.

The move was considered a serious setback for efforts by the government of President F.W. de Klerk to open black-white discussions. De Klerk expressed regret over the violence, but urged the ANC to reconsider its postponement.

Nelson Mandela, the ANC's deputy president, told tens of thousands of supporters that an April 11 meeting with the government was put on hold indefinitely because ''state violence against our people still continues.''

He cited excessive police force against protesters on Monday that left at least nine blacks dead and more than 400 injured in Sebokeng. Police said they opened fire after protesters stoned a police station in the township near Johannesburg and set fire to municipal buildings.

''If the government talks about negotiations on the one hand and massacres our people on the other hand, we cannot tolerate that,'' Mandela said at a packed sports stadium in the southern city of Bisho, capital of the nominally independent Ciskei homeland.

''The conditions for the (ANC's) armed struggle still prevail,'' he added.

Mandela said he acted on instructions from exiled ANC leaders in Lusaka, Zambia, when he called de Klerk on Friday to tell him of the postponement.

He did not say what it would take to reschedule the talks, which have been hailed as a groundbreaking effort to clear the way for extending political rights to the country's 28 million black majority.

The Cabinet minister for black affairs, Constitutional Development Minister Gerrit Viljoen, said the white-led government was ''giving attention to the announcement's implications.'' He did not elaborate.

De Klerk said he was awaiting a full report on the violence, but said the deaths should not be used to derail the proposed talks between black leaders and the government.

Zach de Beer, co-leader of the anti-apartheid Democratic Party in the white chamber of Parliament, said ''the shooting at Sebokeng was a deplorable episode, (but) it can be no excuse for breaking off talks.''

''One can only express the heartfelt hope that the ANC will think again, and quickly,'' de Beer added.

ANC officials and other anti-apartheid leaders on Friday persuaded Mandela to back out of a planned appearance with political rival Mangosuthu Buthelezi, leader of the Zulu homeland.

The two had agreed - on Mandela's initiative - to make a joint call for peace at a rally Monday in Natal Province, where fierce fighting between pro- ANC and pro-Buthelezi blacks has claimed at least 40 lives since Tuesday. Thousand of blacks caught up in the violence have fled their homes.

Mandela, released from 27 years of imprisonment Feb. 11, is the effective head of the ANC while President Oliver Tambo recovers from a stroke in Sweden. But events of the past two days suggest he may not have the freedom to pursue his initiatives without the approval of younger, more militant ANC leaders.

In Lusaka, the ANC said it would hold a meeting within five days to review developments in South Africa.

The organization, the main black group fighting the government, accused security forces of siding with Buthelezi's relatively conservative Inkatha movement in the Natal province factional fighting.

''Whereas in the past the regime's police turned a blind eye to vigilante terror directed at the democratic movement, this week they have actually actively participated in the massacres,'' the ANC statement said.

Mandela condemned the violence in Natal and elsewhere, but his appeals have had no impact. Several weeks ago he told blacks in Natal to throw their weapons ''into the sea.'' Since then, the faction fighting has only intensified.

Supporters of the ANC and Buthelezi's more conservative Inkatha movement battled for political supremacy in Natal since 1986, and at least 4,000 blacks have been killed.

Buthelezi expressed shock at Mandela's decision not to attend a rally Monday in the province.

''People are going to die while they (the ANC) delay,'' said Buthelezi, who like Mandela has made unheeded pleas for an end to the violence.

The government has made clear that the ANC will be only one of several black groups that would be present for formal negotiations on a new constitution.

De Klerk says he wants equal voting rights for all South Africans. But he opposes outright black majority rule and envisions a mechanism that will give the country's 5 million whites veto power on major policy decisions.

The ANC wants a one-person, one-vote democracy.