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

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

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

Ten people had died in clashes there since last Friday.

The BBC's Milton Nkosi reports from Johannesburg.