South Africa has expelled three Rwandan diplomats it linked to an attack on an exiled Rwandan general's Johannesburg home, and Rwanda has retaliated by ordering out six South African diplomats, according to officials.
Three diplomats from the Rwandan mission in Pretoria were ordered out of the country in 48 hours this week. Rwanda's tit-for-tat expulsions followed on Friday.
"We have expelled six S. African diplomats in reciprocity & concern at SA harbouring of dissidents responsible for terrorist attacks in Rwanda," Louise Mushikiwabo, Rwanda's foreign minister, said in a comment on her Twitter account.
The South African diplomats were "coming back home tonight", according to a diplomatic source.
South African foreign affairs officials refused to comment, saying a statement would be issued later.
The row has strained ties between two African states involved in efforts to bring peace to eastern Democratic Republic of Congo (DRC), where South Africa has troops in a UN brigade that fought last year against rebels who UN experts said received support from Rwanda.
Rwanda denied backing the DRC rebels.
Late on Monday, armed men broke into the Johannesburg home of General Faustin Kayumba Nyamwasa, a former Rwandan army chief and an exiled critic of Rwandan President Paul Kagame.
Nyamwasa, who survived an assassination attempt in Johannesburg in 2010, was not in the house at the time.
A diplomatic source, who asked not to be named, told Reuters news agency that South African security services had tracked the attackers.
"It was very clear that they were intelligence personnel attached to the Rwandan embassy," the source said.
Nyamwasa's presence in South Africa has caused diplomatic headaches for the government. After he was shot and wounded in 2010, South Africa's Foreign Ministry described the attack as an assassination attempt by foreign "security operatives".
South Africa then recalled its ambassador to Rwanda in the wake of the incident.
Six men - three Rwandans and three Tanzanians - are on trial accused of trying to kill Nyamwasa.
South African police have also been investigating the New Year's Eve murder in a posh Johannesburg hotel of another exiled Kagame opponent, former Rwandan spy chief Patrick Karegeya.
Karegeya fled to South Africa in 2007 after allegedly plotting a coup against Kagame with Nyamwasa.
Exiled Rwandan opposition members have accused Kagame and his government of being responsible for Karegeya's death and for attacks on Nyamwasa and other overseas-based critics.
The US in January expressed concern over what it called "politically motivated murders of prominent Rwandan exiles".
Embassy closure urged
David Batenga, a nephew of the slain Rwandan spy chief Karegeya, called for the closure of the Rwandan embassy in South Africa.
"It's not an embassy, it's an operation centre for planning missions to kill innocent civilians," he told Reuters.
Etienne Mutabazi, deputy chairman in South Africa of the opposition Rwanda National Congress, of which Karegeya and Nyamwasa were founding members, said the expulsions by South Africa were "long overdue" and called their activities "criminal".
"Diplomats are here to represent their country, they have immunity, but they should not abuse that immunity," he said.
Kagame and senior Rwandan officials have denied any involvement in attacks on exiles, but have called them traitors who should not expect forgiveness or pity.
In January, Kagame, who has won Western praise for rebuilding Rwanda after the 1994 genocide there, defended his nation's right to self-defence against those who "betray" it.
"We didn't do it, but my question is - shouldn't we have done it?" Kagame said at a January 12 prayer breakfast, clearly referring to Karegeya's death but without naming him.
"No one will betray Rwanda and get away with it. Regardless of who you are, there will be consequences."