JOHANNESBURG - A wave of xenophobic attacks escalated in South Africa's seething townships on Monday, with mobs beating foreigners and setting some ablaze in scenes reminiscent of apartheid era violence.

The unrest has killed at least 22 people since last week and increased political instability at a time South Africa is struggling with dire power shortages, rising inflation and growing disaffection among the poor with pro-business policies.

Police fired rubber bullets at rioters in communities around Johannesburg and in the central business district.

Armed with knives, clubs and jugs of petrol, the mobs targeted mostly Zimbabweans and Mozambicans, the biggest groups among immigrants who are accused by the poor of taking jobs and fuelling the high rate of violent crime.

Women were raped, shops and homes looted and dozens of shacks burnt to the ground. Scores have been arrested.

"This is a war," said Lucas Zimila, a 60-year-old Mozambican man who was attacked by a machete-wielding mob while sleeping in his shack in Tembisa, north of Johannesburg, on Sunday night.

"They screamed at me to get out, that I didn't belong here. Then they burned everything in my house," said Zimila, who suffered a five-inch gash in his head. He said five people were killed in the community last weekend.

The unrest is an embarrassment for South Africa, which has vaunted its tolerance since the end of apartheid and hopes to encourage foreign visitors for the soccer World Cup in 2010.

The violence is an indicator of growing anger among those who complain they have been left out by President Thabo Mbeki's policies to promote business and investment. Investors are already worried by growing labour influence in the ruling ANC since Mbeki lost the leadership in December to rival Jacob Zuma.

The foreign-born residents say that far from being criminals they are more often the victims of crime. Several told Reuters organised criminals were using the xenophobic violence as cover to rob and loot.

"We want the army here. The police can't protect us," said Beto Inancio, another Mozambican in Tembisa township.

MANDELA SADDENED

South African newspapers carried photos of a man who was set alight by a mob on the weekend. Callers to radio stations urged authorities to impose curfews and bring in the army to restore order in some of the most violent areas.

The scenes recalled troubles in the townships during apartheid when black liberation activists fought the white minority government's security forces and rival factions. Suspected informants were sometimes burnt to death.

Mbeki and Zuma have called for an end to the violence.

Anti-apartheid icon Nelson Mandela also weighed in, saying he was saddened by rising hatred of foreigners. His Nelson Mandela Foundation issued a statement deploring the attacks and said it was helping children affected by the violence.

Hundreds of immigrants have taken refuge in police stations, churches and government offices.

"It's getting worse. They keep coming here because this is a safe place," said Simon Ramollo, a community activist who was arranging bedding and meals for about 200 foreigners who sought shelter at a community centre.

There are an estimated three million Zimbabweans living in South Africa, most as a result of an economic collapse at home. The violent political crisis since disputed March 29 elections gives little incentive to return home.

Foreigners from poorer African countries have been lured by work in South Africa's mines, farms and homes, and by one of the world's most liberal immigration and refugee policies.

The Democratic Alliance, the main opposition party in South Africa, on Monday blamed Mbeki's government for failing to come up with a comprehensive plan to deal with the waves of migrants that have entered the country in the last quarter of a century.