Clashes pitting the poorest of the poor against one another have focused attention on complaints that South Africa's post-apartheid government has failed to deliver enough jobs, housing and schools to go around. Police brought in reinforcements as violence hopped from slum to slum in scenes reminiscent of the bloodiest days of apartheid. Most of the victims were foreigners in squatter camps. Archbishop Desmond Tutu made an impassioned plea Monday for the violence to end. "Please stop. Please stop the violence now," he said in a statement. "This is not how we behave. These are our sisters and brothers." Tutu said that when South Africans were fighting against apartheid they had been supported by people around the world, and particularly in Africa. "We can't repay them by killing their children. We can't disgrace our struggle by these acts of violence," he said. President Thabo Mbeki also reiterated his call for an immediate stop to the attacks saying "nothing can justify it" and that police will get to the "root of this anarchy." South Africans are struggling to buy food as prices rise. Unemployment is 23 percent and many complain the government hasn't worked fast enough to build houses, schools and hospitals for the long-neglected black majority. Foreigners have been targeted because they are seen as competing for scarce resources - and because they were the closest targets on hand for the poor. Leyton Salaman, a 35-year-old tiler from Malawi, said the trouble started slowly in Ramaphosa, a collection of shacks among the mine dumps and warehouses east of Johannesburg. A few foreigners were beaten Friday. Saturday, shacks were set alight. When the killing started Sunday, Salaman and hundreds of others fled to the neighboring community of Reiger Park, where he sat in a church yard Monday. "These people, they said, `You are taking our jobs,"' said Salaman, who has lived and worked in South Africa for eight years. "Now they just come and take our things." Police spokesman Govindsamy Mariemuthoo said that, since the violence broke out last week, 22 people had been killed. Mariemuthoo said more than 200 people had been arrested on charges including murder, rape and robbery. Mariemuthoo said police reservists and officers from other regions were being called in to help. The South African Red Cross and other aid groups appealed for funds to care for the hundreds of people who have been displaced. Some victims were set alight. Jonathan Whittal, a humanitarian affairs officer with Medecins Sans Frontieres, said his group had seen cases of rape as well as gunshot and other wounds. "The violence is extreme," Whittal said, calling for a broader, more coordinated humanitarian response. He also said security for immigrants would remain a concern even after the current outbreak is extinguished, and the underlying causes would have to be addressed. The violence would likely only add to South Africa's image as a crime capital - it has a murder rate of more than 50 per day - just as it prepares to host visitors from around the world for the 2010 soccer World Cup. While still shockingly high, crime rates in South Africa have been slowly dropping. Many South Africans, though, say they believe crime is rising, questioning the official statistics in one measure of distrust of the government. The Nelson Mandela Foundation was among the organizations called for calm. The foundation noted that the former president had sponsored projects aimed at helping immigrants integrate into South African communities. In a statement, the foundation repeated a plea that Mandela, South Africa's first black president, made during an outbreak of xenophobic violence in 1995: "We cannot blame other people for our troubles." President Mbeki said in a statement issued by his office that he was being kept informed of developments and that "law-enforcement agencies must and will respond with the requisite measures against anyone found to be involved in these attacks." "Citizens from other countries on the African continent and beyond are as human as we are and deserve to be treated with respect and dignity," he said. "As South Africans, we must recognize and fully appreciate that we are bound together with other Africans by history, culture, economics and, above all, by destiny." Zimbabwean Gina Themba nursed her 2-week-old daughter on the floor of a room at a police station in downtown Johannesburg Monday. She said neighbors among whom she had lived for three years broke into her house the night before and demanded she leave. She said she did not understand why. Such scenes were repeated in pockets across the Johannesburg region. Foreigners fled to police stations, churches and community halls. At one police station-turned-refugee camp, a young man wandered with a loaf of bread and a knife, selling slices for a 1 rand (about 15 US cents) each, in a display of immigrant entrepreneurship that has sparked resentment. Vincent Williams, head of an immigration research project of the independent Institute for Democracy in South Africa, said accusations that immigrants take jobs from natives, or that they are responsible for crime, are heard in many places around the world. He said it was rare for such sentiment to erupt into sustained violence, but this was not the first time it has done so in South Africa. The last serious outbreak was just after apartheid ended in 1994. "We've known for quite a while that levels of xenophobia in South Africa are high," Williams said. He said speculation about the reasons has touched on the isolation created by apartheid as well as fears the institutionalized racism of the past has left even black South Africans suspicious of black foreigners. Zimbabweans, Malawians, Mozambicans and others from elsewhere in Africa have been the main targets of the violence. President Thabo Mbeki said Sunday that he would set up an expert panel to investigate. Williams said the panel should probe whether the violence has been orchestrated, perhaps by an as yet unknown anti-immigrant group. Williams also called for a public awareness campaign to ensure immigrants as well as native-born South Africans understood their rights, and understood that while immigrants may take jobs here, they also buy South African goods and services, and pay taxes. Some South Africans were moved to help foreigners, dropping by the impromptu shelters with food, clothing, blankets and other donations. Lisa Letsoso, an 18-year-old South African living in the Ramaphosa squatter camp, was up all night working with church groups distributing aid to people from the camp who had fled to Reiger Park. "The South African are fighting the foreigners. Now the foreigners are fighting back," Letsoso said. "Everyone is suffering."