SOWETO, SOUTH AFRICA, SEPT. 9 -- At least 26 more people were killed and about 50 injured here in a fresh outbreak of factional violence sparked by a pre-dawn armed raid on a squatter community in this sprawling black township near Johannesburg.

Thirteen people died in that attack, which triggered a day of running battles between police and Soweto residents that caused the rest of the casualties and which began to subside only after dark.

Witnesses identified the raiders who struck at the squatter settlement as Zulu supporters of Chief Mangosutho Buthelezi's Inkatha Movement housed in a nearby migrant workers' hostel, and many alleged again that whites with blackened faces were among them.

It was the third time in less than a week that allegations of white involvement in the township violence have been made, prompting speculation that it is being fanned by white extremists trying to destabilize the negotiating process underway between President Frederik W. de Klerk's government and the African National Congress.

A crowd gathered later at the migrant hostel, threatening to demolish it and drive out the heavily armed dwellers, but police dispersed them with tear gas, rubber bullets and shotguns.

Clashes continued throughout the day between groups of young ANC supporters and police, whom the residents accuse of siding with Inkatha in a bloody conflict for dominance between Inkatha and the ANC that has spread from Natal province to the Johannesburg ghettos over the past six weeks, taking about 600 lives.

Many Soweto streets were blocked by barricades of rocks and scrap metal set up by youths to prevent police vehicles from entering. One group of young men also threw a barricade across a railroad track after claiming they had been fired on from passing trains.

The squatter settlement, a jumble of tin shanties that had sprung up on a stretch of open ground beside the railroad on the western fringes of Soweto, was said to have been attacked by a about 100 hostel dwellers.

Residents of the settlement said the attackers rampaged through the narrow alleyways in the pre-dawn darkness, firing guns and hacking at people with machetes. Several residents said they had seen whites, their faces blackened with soot, among the attackers.

Similar claims were made after an Aug. 4 attack in Sebokeng township, south of Johannesburg, in which 36 people were slain, and again two days later, when gunmen ran onto a train station platform in Johannesburg firing randomly and killing six black commuters.

Several Johannesburg newspapers have suggested that there may be a "third force" of white extremists fanning the violence to destabilize the delicate negotiations between the government and the ANC on a new power-sharing constitution.

On Saturday, one paper quoted a spokeswoman at police headquarters in Pretoria, Lt. Nina Barkhuizen, as saying that such a possibility is being investigated.

However, many blacks in the townships continue to accuse police of complicity in the violence. The Rev. Frank Chikane, general secretary of the South African Council of Churches, said after visiting the squatter settlement today that he had gathered enough evidence to show that "police are involved in killing us."

People in the squatter community claimed they also had been fired on from passing trains, suggesting -- without offering any evidence -- that police traveling in the trains had done the shooting.

Today, as police repeatedly opened fire on groups of angry blacks with tear gas, rubber bullets and shotguns and Soweto youths hurled stones and gasoline bombs back at them, it was impossible to obtain independent verification of these claims.

In mid-morning, a group of armed youths gathered at the hostel where the settlement attackers were said to be housed, threatening to demolish it and drive out the inhabitants.

After police dispersed the youths, the mayor of Soweto, Sam Mkhwanazi, addressed a group of about 500 heavily armed hostel dwellers, appealing for peace and asking them to elect representatives to attend a peace conference at his office.

Later, the hostel dwellers, most of them wearing red headbands that Inkatha supporters use to identify themselves, formed two groups and jogged up and down the hostel grounds singing war songs and brandishing an array of clubs, spears and battle axes.