JOHANNESBURG, SOUTH AFRICA, JAN. 12 (SATURDAY) -- Thirty people were killed and 26 wounded today when gunmen sprayed bullets at supporters of the African National Congress in the black township of Sebokeng, South African police said.

The unidentified gunmen drove up in a car to a house surrounded by tents in which ANC supporters sat or lay at dawn during a funeral vigil for an ANC member who had been killed, police spokesman Col. Johan Mostert said. The gunmen opened fire on the mourners with AK-47 assault rifles, he said.

The attack was one of the deadliest in months in South Africa, where more than 1,000 people have been killed in fighting between supporters of the ANC, led by Nelson Mandela, and the backers, mostly ethnic Zulus, of Mangosuthu Buthelezi.

Sebokeng was the scene last year of some of the worst fighting in that rivalry. Many township residents are loyal to the ANC, and clashed with migrant workers loyal to Buthelezi's Inkatha Freedom Party who live in crowded workers' hostels.

The violence subsided towards the end of 1990 but many of the townships have remained tense, with government troops patrolling the migrant worker hostels.

The mourners killed today were friends or relatives of an ANC member kidnapped and killed by an unknown group of gunmen. ANC spokeswoman Gill Marcus said the ANC believed today's attack had been carried out by the same group of gunmen. The community in Sebokeng had been warned such an attack would take place, she said.