NAIROBI, Kenya Jun 30 – Thousands of people have marched in South Africa’s main cities to demand that all undocumented migrants leave the country.Police officers – backed by private security guards – have been deployed because of fears that protests could turn violent. Anti-migrant groups had set Tuesday as the deadline for undocumented migrants to leave.Many foreigners have already fled to escape violence and intimidation. South African police say 25,000 have been repatriated so far. Most are from other African countries.One undocumented Malawian told the BBC he was “happy to be going back” but “heartbroken” to be leaving behind four young children.The Ministry of Police said the protests have largely been peaceful across the country, with isolated incidents of looting and attempted looting.In Johannesburg, the financial capital, shops in the city centre were closed, while police visibility is high on major streets.Some protesters threw bricks, breaking the windows of some homes in Yeoville, a suburb in Johannesburg where many African migrants live.In a neighbourhood in Germiston, about 15km (nine miles) from Johannesburg, demonstrators went to homes, evicting residents they suspected were foreign nationals and handing them over to police officers, insisting they check their documentation, local media report.