The immigrants, mostly African, have been housed at police stations and tents, as angry locals vowed to push them out -- in South Africa's latest case of xenophobic unrest.
"They said they were intimidated to vacate their homes by locals and came to us because they feared for their lives," police spokesman Thulani Zwane said.
Violent clashes between immigrants and locals often flare up in South Africa, as impoverished residents accuse them of taking their jobs.
Police said no deaths had been reported since the violence started.
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Police yesterday broke up a march by a group of foreign nationals who were protesting against the violence, firing water cannons and tear gas.
Police said the march was illegal. Spokesman Eugene Msomi said the crowd had to be dispersed when they failed to follow orders to do so.
"They were informed in writing the day before not to march due to prevailing safety concerns," Msomi said.
The attacks came days after Zulu king Goodwill Zwelithini publicly said immigrants should "pack their bags and leave" the country.
Similar statements have been made by President Jacob Zuma's son Edward.
Locals and African immigrants in South African often compete for scarce jobs, making them a target for violence and intimidation.
Early this year, foreign shopkeepers in and around Soweto, south of Johannesburg, were forced to vacate their premises after violence and looting broke out.
The government condemned the violence and sent mediation teams to intervene.
In 2008, 62 people were killed in xenophobic violence in Johannesburg townships.