South African police said yesterday five white extremists have been charged with terrorism over an alleged plot to bomb black townships, but insisted there was no threat to the football World Cup.

The men were among seven people arrested last month in the northeastern town of Phalaborwa, near the Kruger National Park, said Musa Zondi, spokesman for the police special investigations unit.

"They were conspiring to engage in terrorist activities, which includes the fact that they wanted to blow up areas in which black people live," he said.

The Phalaborwa group were arrested on suspicion of desecrating the grave of a senior black politician, but subsequently directed police to a weapons and explosives cache, he said.

All seven were initially charged with terrorism, but charges against two of them were withdrawn yesterday. Of those charged, one has been released on bail and four are in custody.

"They were working on their own. I don't know if there was a master plan in place but threats are always serious," said Mr Zondi.

The killing last month of white supremacist Eugene Terre'-Blanche last month heightened fears of racial violence ahead of the expected arrival of nearly 400,000 football tourists for the June 11-July 11 World Cup.

But police chief Bheki Cele insisted the extremists posed "absolutely" no threat to the World Cup which starts on June 11.