South Africa has expelled three Rwandan diplomats in connection with an attack on the home of an exiled Rwandan dissident, diplomatic sources say.
Rwanda responded by ordering out six South African envoys, officials said.
The moves come after armed men raided the Johannesburg home of Kayumba Nyamwasa, a Rwandan former chief of staff, earlier this week.
Lt Gen Nyamwasa, an exiled critic of Rwandan President Paul Kagame, was not at home.
However, the property was ransacked and a computer and some documents were taken.