PRETORIA, South Africa (AP) — Tension is rising in South Africa’s platinum mine sector, where police are struggling to keep order after three miners working in defiance of a strike were killed in separate incidents.

The platinum-mining area around Rustenburg town was quiet Tuesday after the violence that had started on the weekend, the South African Press Association reported. It said one slain miner was stabbed, another was set afire and a third miner and his wife were strangled to death.