The South African army has been deployed to areas in that remain volatile after a spate of attacks targeting immigrants, the defense minister announced on Tuesday.

Soldiers have already been sent to support police in troubled areas, Defense Minister Nosiviwe Mapisa-Nqakula said in a live broadcast.

The minister made the announcement in Alexandra, a Johannesburg township where a Zimbabwean couple survived a shooting overnight. The man was shot in the neck and his partner was shot in her leg, the minister said. Both Zimbabweans were treated and discharged from hospital.

In the same Alexandra neighborhood, a Mozambican man was stabbed to death by four South African men over the weekend. Photographs of the stabbing were published in a local newspaper on Sunday. The four South African men appeared in court on Tuesday and remain in police custody, said Velekhaya Mgobhozi, the National Prosecuting Authority spokesman.

Troops were also sent to Durban, the coastal city where the attacks on foreigners began, Mapisa-Nqakula said.

Many Malawians living in South Africa have been attacked in the violence. In Malawi, nearly 2,000 protesters marched to the South African High Commission, demonstrating against the wave of violence, said Billy Mayaya, a human rights activist. A diplomat at the South African mission said earlier that there were several hundred marchers.

The group marched in the capital Lilongwe, carrying placards and singing songs. Some carried posters that read "South Africa, why kill your fellow blacks?"

The march organizers demanded that the South African government do more to protect immigrants and handed a petition to South African High Commissioner Cassandra Mbuyane-Mokone.

The recent spate of attacks in South Africa have mainly affected immigrants from African states, like Malawi, Mozambique and Zimbabwe, according to a statement from the aid group, Doctors Without Borders.

Nearly 400 Malawians returned home on Monday, traveling overnight by bus from South Africa, Malawi's Information Minister Kondwani Nankhumwa said.

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Associated Press writer Raphael Tenthani contributed to this report from Lilongwe, Malawi.