Police say residents in the township of Alexandra, north of Johannesburg, have put up posters warning foreigners to vacate RDP houses.

"They are delivering pamphlets to those living in RDP houses," said Warrant Officer Kay Makhubela.

The SABC reported that residents had given the foreigners seven days to vacate the houses in the township.

Residents had hung up posters which read: "You are violating our rights to own our RDP houses".

In one of the letters handed out, they said: "The residents of Alexandra don't want ... xenophobia unless you give them a cause to do so", the public broadcaster reported.

In another letter they said: "We demand that you vacate at your own free will without being pushed like animals or aliens".

Tensions were simmering between residents and foreigners.