A veteran African nationalist fighting for black-majority rule in South Africa was shot to death last night in his car outside his home in a suburb of Salisbury, police said today.

The victim was Joe Gqabi, 52, head of the African National Congress (ANC) here. Zimbabwean officials blamed the slaying on the South African government. They promised to continue supporting the congress.

There was no immediate reaction from South Africa.

Gqabi's murder was the first known violent incident in Zimbabwe involving the congress, which has been responsible for a rash of bombings in South Africa during the last year. The killing comes at a time of increased tension in the relations between Pretoria and the new black government in Salisbury.

Police said Gqabi's body was found in his car by his secretary when she returned to the house at 12:15 a.m. Eighteen spent cartridges were in the driveway. A .22-caliber Beretta pistol with a silencer was near the body.

Police sources said two weapons were probably used. The body was riddled with bullet holes, they said.

A government statement issued by Information Minister Nathan Shamuyarira said Gqabi was shot at point-blank range while driving out of the front yard of the house in Ashdown Park, a middle-class suburb 10 miles from downtown Salisbury.

"The government believes this brutal act to be the dirty work of unscrupulous agents of the racist South Africa regime," Shamuyarira said.

South Africa has increasingly attached neighboring Angola, Mozambique and Zambia in the last year, but hostilities in its relationship with Zimbabwe have been limited to words.

Zimbabwean Prime Minister Robert Mugabe, trying to maintain a delicate balance between his need to support the African liberation struggle and his country's economic dependence on South Africa, has allowed the African National Congress to establish a low-profile presence in Salisbury. But Mugabe repeatedly has said that no guerilla activity would be allowed on Zimbabwean soil.

Unlike Zambia and Tanzania, Zimbabwe has not granted anti-South African groups any form of diplomatic recognition. They have no formal offices.

The distinction seems to have been lost or South Africa, however. In May, South African Police Minister Louis Le Grange said that if Mugabe persisted in his support of the congress, "we will not stand by idly with our hands tied behind our backs."

Prime Minister Pieter Botha strengthened the impression that it would not take guerilla action from Zimbabwean territory to bring about South African action.

"The ANC will only open offices if they wish to organize direct action," he said. "Should that happe we will deal with it in the way we find proper."