As winter sets in, the Zimbabwean government has launched another operation to purge the capital, Harare, of "illegal" homes and market stalls in an effort to "clean" the city.

The demolitions began at the crack of dawn on Thursday, when truckloads of municipal police raided the high-density suburb of Glen Norah in Harare and brought down "illegal" structures with crowbars and set them alight. More than 400 people were affected, including school children.

Last winter the government launched 'Operation Murambatsvina' (Drive out Filth) in cities and towns across the country. The campaign to demolish informal settlements left over 700,000 people homeless or without a source of income and was met with widespread condemnation from human rights bodies, including the UN.

Martha Manda, a widow with two children, was inconsolable as she watched her house go up in flames on Thursday. "I have nowhere to go now. My grandparents came from Malawi and settled in this country as migrant labourers. As a result, I cannot go back to Malawi because I don't know anybody there."

Authorities said the people being weeded out of urban areas should return to their rural villages of origin, but although many have done so, the descendants of migrant workers from Mozambique, Malawi and Zambia have been left in a quandary.

The mayor of Harare, Sekesai Makwavarara, informed residents of the new operation, saying: "as residents you should support the council and government when they embark on the clean-up exercise".

Two weeks ago the government launched what it called 'Operation Round-up', in which street children and homeless people were picked up and dumped at a farm outside Harare.

Precious Shumba, a spokesman for the Combined Harare Residents Association, said they were trying to help those who had been affected. "We are trying to get aid for the people, like food and blankets, especially because this unfortunate exercise has again been launched in the middle of winter."

Humanitarian bodies have condemned the latest demolitions. Crisis Coalition, a grouping of NGOs, said, "We have to unite to defend our rights, which are not privileged gifts parcelled out by generous politicians but [are] inalienable because we are human and legitimate citizens of this country. No one, regardless of their political, economic and social standing, should be given the right to dump the lives of the citizens of this country into misery."

Gabriel Chaibva, spokesman for the pro-senate faction of the opposition Movement for Democratic Change, also condemned the destruction. "Harare officials have demonstrated their insensitivity to the plight of the poor - the demolitions have been carried out with brutal force and in cold winter season, when it is clear that the victims of the demolitions, especially the elderly and children, are likely to be exposed to the vagaries of cold weather."