JOHANNESBURG (Reuters) - South African police said on Wednesday that five people had been arrested in connection with a petrol bomb attack on a bus that killed six workers on their way to the Modikwa platinum mine earlier this week.

The platinum belt has been a flashpoint of violence rooted in community grievances over jobs, revenue flows and conflict between rival unions that threatens production in the world’s top producer of the precious metal.

The accused will appear in court on Thursday on charges of attempted murder, murder and malicious damage to property, police spokesman Brigadier Motlafela Mojapelo said.

The motive for the attack, which is still being investigated, was unknown, Mojapelo added.

The attack occurred on Monday night near the town of Burgersfort in northern Limpopo province while the workers were being driven to the Modikwa mine operated by African Rainbow Minerals and Anglo American Platinum.

Production at the mine, which produces around 300,000 ounces of platinum group metals annually, was temporarily halted.