Miners stoned a white security officer to death and two blacks were killed by rubber bullets in a clash last night at a gold mine near here as South African whites reacted with alarm and anger to the deaths of six whites at a resort earlier in the day.

The killing of the white man, when an angry crowd of blacks stoned security personnel, brought to 14 the number of whites who have died in racial violence during the past eight days. The two blacks were killed when guards opened fire on the assailants. The previous toll of whites, in 16 months of race-related violence, had been six, compared with 950 blacks killed in that time.

Even liberal whites who have been advocating negotiations with the underground African National Congress joined the general outcry against the organization, to which the government and most of the press attributed the six killings and the wounding of 61 white shoppers at the resort of Amanzimtoti.

Progovernment newspapers said the apparent switch to full-scale terrorism by the ANC justified the government's refusal to negotiate with the organization or release its imprisoned leader, Nelson Mandela, as long as the ANC refused to renounce the use of violence.

However, the ANC still has not officially acknowledged responsibility for the bombing.

While the ANC's official spokesman, Tom Sibina, issued a terse "no comment" to press inquiries at the organization's exiled headquarters in Lusaka, Zambia, national executive member Johnny Makatini hinted in a U.S. National Public Radio interview today that the shopping-center attack may have been an unauthorized action by a congress militant.

"The ANC's position up to now has been to rigidly avoid any operation that could entail the loss of innocent lives," Makatini said. "The ANC has never kidnaped or hijacked anyone and has never attacked any civilians. The ANC has not abandoned that approach. If it is one of our militants who has carried out this operation, it would be that he acted on his own."

Makatini said that it took time to get confirmation from within South Africa about specific operations, and that no report had been received yet on the shopping-center bomb. Asked whether the ANC would be investigating the explosion, Makatini replied: "Oh, definitely."

[In Washington, a State Department spokesman described recent incidents in South Africa and along its borders as "extremely troubling. They threaten to intensify the tragic cycle of violence and retribution, which has for too long substituted for political dialogue and diplomacy in the region."]

The spate of white deaths during the past week, including five women and six children, has unleashed a surge of emotion in the white community.

Until now, whites have been relatively remote from the violence, which has been confined to the segregated black townships. White South Africans have seen little of it on the state-controlled television service, which has never sent cameras into the troubled townships.

The sudden sense of alarm is overlaid with anger at the death of innocent civilians, especially in the shopping-center blast, and there are many calls for retribution against the ANC.

Law and Order Minister Louis le Grange pledged today that the police would work round the clock to track down those responsible for the shopping center bomb, and the government issued an appeal for contributions to a special fund for victims of the blast.

Bishop Desmond Tutu, winner of the 1984 Nobel Peace Prize, issued a statement deploring the increasing spiral of violence and blaming it on "the vicious and repressive system of apartheid."

The Cape Times, which recently defied press restrictions to publish a 3,500-word interview with ANC President Oliver Tambo and has been in the forefront of calls for the organization to be legalized, said in an editorial today that "those who would act as apologists for such deeds must be convinced that they are grievously wrong."

The country's leading financial daily, Business Day, said that by its attacks on white civilians, the ANC had "put itself beyond negotiations."

"After yesterday's bomb atrocity, whatever slim prospects there were of dealing with the ANC are surely dead," the newspaper said.

Businessmen have been among those urging the government to negotiate with the ANC, and some businessmen recently met with the organization's leaders in Zambia.

"We wonder exactly what the ANC is trying to achieve," Business Day said in its editorial. "It has never been better placed to become part of peace negotiations. But who now, businessman, clergyman or student, will be seen talking to the ANC?"

"Further, any prospects for the release of Nelson Mandela have faded. Is this perhaps a deliberate strategy of the current ANC leadership?" the newspaper asked.