Conservative black "vigilantes," said to be supported by white police, widened their control today over militant leftist areas of the Crossroads squatter camp as violence continued to rise with the approach of the anniversary Monday of the 1976 Soweto riots.

At least eight more persons were killed as bitter fighting between the rival black factions raged through the camp east of Cape Town. In eastern Transvaal province, a white youth and two black farm laborers were injured in landmine explosions.

Another seven persons, all black, died in other incidents of widespread violence.

Denying allegations of police complicity in the camp violence, Lt. Attie Loubscher, who is in charge of police operations in Crossroads, said today: "We definitely did not and will not take sides in the unrest. It is our duty to maintain law and order, and we will do exactly that."

Independent observers and residents of the stricken camp today repeated accusations that the police were aiding the vigilantes. The main opposition party in the white-dominated Parliament, the Progressive Federal Party, called for an inquiry into the allegations.

"This alternative method of forced removal surely cannot be encouraged," said the party's long-time civil rights campaigner, Helen Suzman.

The accusation is that the leader of the main sector of the squatter complex, called Old Crossroads, has agreed with white authorities to drive out the squatters from a number of satellite camps that have sprung up around the central one.

In return, Old Crossroads would be upgraded into a township with improved houses, paved streets and athletic fields.

Critics charge that the administration is trying to achieve its long-sought objective of removing the squatter complex, at the same time crushing black radicals who have made the satellite camps their stronghold.

Today's casualties in Crossroads brought to 14 the number of persons killed since renewed fighting began there yesterday between the black radicals, known as "comrades," and the vigilantes.

At least 20 others, including four journalists, were wounded in today's violence.

One of the journalists, George D'Arth, a television cameraman for the British ITN network, was reported in fair condition after being hacked about the head by vigilantes wielding machetes. His black sound technician, Andile Fasi, sustained minor injuries.

Local reporter Bert van Hees and French photographer Patrick Durand both were wounded in the arm by bullets as the two factions involved in the fighting and the police exchanged gunfire among the burning shanties.

Van Hees was traveling with a police escort in an armored personnel carrier when a bullet ricocheted off the side of the vehicle and struck him. Groups of comrades opened fire on police patrols several times through the day.

Thousands more people fled today as the vigilantes again invaded a sector of the squatter complex called KTC camp, setting fire to shanties. Welfare workers estimate that 2,000 shanties in the camp have been destroyed since yesterday, adding another 20,000 people to the 35,000 rendered homeless when vigilante fighters demolished three other camps in the Crossroads complex last month.

In eastern Transvaal, the white youth and two black farm laborers were injured in two separate landmine explosions near the town of Volksrust. The youth, Martin Coetzer, 18, was taken by helicopter to a hospital in Johannesburg where his condition was described tonight as critical.

The mine was thought to have been planted on a farm road by guerrillas of the African National Congress, the outlawed black nationalist organization.

Three hours later a tractor detonated another mine on a farm six miles away. The two laborers, Elias Shabangu and Lucas Lushaba, who were riding on the tractor, were slightly injured. Fighting also erupted between rival black youth groups today in Johannesburg's troubled Alexandra township after the leader of one of the groups was shot to death during a meeting in a church last night.

Sources in the township said Mahlomola Mabizela, chairman of the Alexandra Students Congress, was hit in the head by a bullet fired through a window of the church.

In Cape Town, two new security bills, which the government has been trying to rush through Parliament before the Soweto anniversary, were still deadlocked in a joint committee of the racially segregated houses. Asian and mixed-race representatives are refusing to agree to clauses that provide for detention without charges.

Official sources suggest that the government might declare a state of emergency or martial law if the bills continue to be delayed.