Due to an dediting error, the report yesterday about black riots in South Africa incorrectly stated that the African National Congress was formed in 1960. The ANC was founded in 1912.

Fourteen people were killed and hundreds were injured today as rioting swept through several black townships near Johannesburg. A number of fires were raging late tonight.

Convoys of heavily armed police and troops moved into some of the townships after dark. Reports of rioting and shooting were continuing after 10 p.m.

It was the worst outbreak of violence in South Africa's black townships since the Soweto riots of 1976, which continued for months and left more than 600 dead.

A bomb explosion ripped through the fourth floor of a government building in central Johannesburg today, causing extensive damage and injuring four people.

It was the third bomb explosion in two weeks in downtown Johannesburg.

The violence coincided with the formal implementation of a controversial new constitution which many blacks have opposed.

It erupted after two weeks of tension and sporadic clashes between police and black students, who have been campaigning for a boycott of elections under the new constitution.

Soweto was quiet today, but Sharpeville township, site of a 1960 massacre in which police killed 64 black passive resisters, was the scene of some of the worst violence.

Rioters there hacked the deputy mayor of the township, Sam Dlamini, to death in the street, then put his body in his car and set it ablaze.

Another senior member of the black council that administers Sharpeville and two adjoining townships, Esau Mahlatsi, was beaten to death.

Police said they found two charred bodies in the burned-out house of a third council member.

The rioters set up barricades in the streets of Sharpeville and adjoining townships. They burned and looted shops and beer halls and stoned and overturned cars, according to police reports. A number of gasoline bombs were thrown through windows and set houses afire.

Police used rubber bullets and tear gas to disperse the rioters, and several times they also opened fire with shotguns.

A black reporter, Sol Makgatlubane, described the scene in Sharpeville as a "battle zone" as police opened fire on groups of youths. He said the streets were littered with stones and debris.

Government buildings, a post office, stores, supermarkets and council members' houses also were set afire in the adjoining townships of Boipatong and Sebokeng.

An official at a hospital in Sebokeng township said more than 200 people were treated there for injuries and 135 were admitted, six of them in serious condition.

Seven policemen were among the 400 or more believed to have been hurt.

There were also reports of rioting from Tembisa township, east of Johannesburg, and Mamelodi township, north of Pretoria.

The immediate cause of the riots appears to have been a decision by the black council that administers several of the townships to increase rents and electric rates.

Residents joined a stay-home demonstration and students boycotted classes. Groups then began marching through the streets, where rioting and clashes with the police began.

The violence followed two weeks of mounting tension between police and black groups that campaigned for a boycott of elections held under the new constitution.

A number of boycott campaigners were arrested, and club-swinging police charged antielection groups that demonstrated near polling stations, claiming that they were intimidating people who wanted to vote.

Several times the scattered demonstrators retaliated by stoning the police and overturning vehicles.

The violence increased over the weekend when students and police clashed in a number of townships.

Seven young blacks were killed in these weekend clashes, including Thabo Sibeko, 6; Joyce Nzama, 9, and Isaac Embonani, 14.

As tension mounted, Frederik van Zyl Slabbert, leader of the main white opposition party, the Progressive Federal Party, urged the government to act speedily to curb "heavy-handed" action by the police.

The minister of law and order, Louis Le Grange, announced that he had ordered an inquiry into the shooting of the children.

"I do not know if more force was used than was necessary," Le Grange said last night. "All I know is that kids have been killed and I want a full report."

As the reports of today's violence came in, the South African Council of Churches issued a statement urging the authorities to show restraint.

"We deplore violence, but we have kept warning that we have a highly volatile situation and we urge the authorities to be sensitive," the statement said.

The bomb that shook downtown Johannesburg today ripped through the fourth floor of a building belonging to the Department of Internal Affairs seven minutes after closing time, when workers had left. Four people in an adjoining building were injured by flying glass.

The other two bomb attacks that have occurred in downtown Johannesburg over the past two weeks also took place after the offices had closed for the day and most workers had left.

The insurgent African National Congress, which is believed to be responsible for the bomb attacks, has stated that its policy is to strike at government installations and military targets and to avoid causing civilian casualties as far as possible. The ANC was formed after the Sharpeville massacre of 1960, when police fired machine guns into crowds of demonstrators.