Police in South Africa have opened fire during clashes with striking workers at Lonmin platinum mine in Marikana, leaving at least seven people dead, witnesses say.

South African media reports put the death toll at 12 or even higher.

Police opened fire after miners carrying machetes defied an ultimatum to disarm, reports from the scene say.

The mine has been at the centre of a violent industrial dispute exacerbated by inter-union tensions.

Police in South Africa have opened fire during clashes with striking workers at Lonmin platinum mine in Marikana, leaving at least seven people dead

Ten people had previously died as a result of clashes since last Friday.

The striking miners had gathered on a rocky hill near Marikana, the third-largest platinum mine in the world.

Some union leaders and police had tried in vain to disperse the crowd, some of whom said they were prepared to die on the hill.

During the clashes, missiles – thought to be either petrol bombs or grenades – were thrown at police, who responded by opening fire, eyewitnesses said.

“There are bodies on the ground; I saw one with a bullet wound on the forehead,” said one eyewitness.

The recent violence was initially thought to have been triggered by a turf war between the long-established National Union of Mineworkers (NUM) and the newly-formed Association of Mineworkers and Construction Union (AMCU), which is more militant.

However, the AMCU has since demanded a pay rise of 12,000 rand ($1,500) per month.

Lonmin said in a statement on Thursday that the strike was illegal and that any striking workers who did not return to work by Friday would be sacked.

The company said it had missed six days of production as a result of the unrest, and estimated it would lose around 2% of its normal yearly output of saleable platinum. Lonmin’ share price dropped by more than 6% on Thursday on the London Stock Exchange.

The violence has shocked South Africans, with many finding the scenes reminiscent of how the apartheid regime dealt with protests.