JOHANNESBURG, DEC. 3 -- The government imposed a curfew on four black townships around this city tonight and sent in police and army reinforcements after two days of fighting among blacks that has left at least 71 persons dead.

Police said they had found the bodies of 52 people, most of whom had been killed in a pre-dawn attack today by what witnesses called a Zulu impi, a traditional warrior military unit, on people in Tokoza township southeast of Johannesburg.

Police said eight other bodies were found in Tembisa, six in Katlehong and five in Sebokeng, all townships where supporters of the African National Congress and the Inkatha Freedom Party have been fighting for political influence.

It was not immediately clear whether all the victims had been killed in fighting during the night or some had died earlier during the weekend. It was also not known whether there was any direct connection between the incidents in the four townships. Tokoza and Katlehong are adjacent to each other southeast of Johannesburg, but Sebokeng is much farther south, outside Vereeniging, while Tembisa is located north of the city.

Tonight, Law and Order Minister Adriaan Vlok imposed a curfew on Tokoza, Katlehong and two other troubled townships, Vosloorus and Bekkersdal.

The violence raised fears of a repetition of fighting between supporters of the ANC and Inkatha, led by Chief Mangosuthu Buthelezi, that occurred in the Transvaal townships last summer and claimed more than 750 lives.

The ANC, led by Nelson Mandela, and Buthelezi traded charges today over who was responsible for the new violence. The ANC issued a statement calling the death toll "a tragedy for our entire nation" and said those responsible were jeopardizing the peace process.

It accused the police of aiding Inkatha Zulu fighters and charged that the violence was "systematically orchestrated, utilizing trained death squads for the purpose of destabilizing and weakening the ANC."

Buthelezi said he was "disturbed and alarmed" by the violence and took issue with ANC allegations that those involved in the attacks were Inkatha members. He attributed the violence to rivalry between the Zulu and Xhosa, South Africa's two largest ethnic groups.

Buthelezi said he objected to reports in which blame for the violence was "automatically apportioned to so-called impis of the Inkatha Freedom Party."