Dozens of people were killed after South African police opened fire on hundreds of workers on a wildcat strike at a platinum mine, in the deadliest day of protest since apartheid.

Police gave a toll of 30 and rising, while the powerful National Union of Mineworkers said 36 had died in clashes at the Marikana mine broadcast repeatedly on national television.

A force of mostly black officers in bulletproof vests, some on horseback, fired at a crowd of black workers armed with spears, clubs and machetes, with some gunfire heard from the workers’ camp as well.

Police said the workers were advancing on them with guns and machetes.

“The police were directing (unrolling) the barbed wire … when people had guns, and people were advancing as I say, with their pangas (machetes) and everything else including firearms,” police minister Nathi Mthethwa said, putting the death toll at more than 30.

“A lot of people were injured and the number keeps on going up,” he told local radio.