SOWETO, SOUTH AFRICA -- As dusk fell, they stood looking down forlornly at their meager, battered household belongings scattered across the grass of an open field under the squashed roofs and tin sidings of their shacks.

The police had come to Dobsonville Thursday morning at 8 with two bulldozers and leveled 60 to 70 flimsy shanties, making 300 to 400 people instantly homeless. All day, the squatters skirmished with the police, some trying to rebuild their shacks only to be arrested for their efforts.

All around Johannesburg, this scene is being repeated as black and white township councils, backed by the South African police, move to halt the squatter camps going up helter-skelter around them, part of an upsurge in black migration to cities all across South Africa.

In Tokaza, south of Johannesburg, police and squatters fought a bloody battle last Wednesday. Two people were killed and 25 injured, and 200 shacks were destroyed at the Phola Park squatters camp there.

Dobsonville sits on the northwest corner of Soweto, the sprawling black township 12 miles southwest of Johannesburg. The township is home to more than 2 million blacks. Throughout Soweto, there are an estimated 97,000 backyard shack-dwellers paying as much as $40 a month rent and subject to the day-to-day whims of their landlords. Some houses have as many as four shacks in their backyards.

It is unclear why town councils have decided to clear away these mushrooming squatter camps in the middle of the Southern Hemisphere's winter, when temperatures fall to the mid-30s at night.

Longtime foreign observers here say there seems to be an upsurge in squatter removals every winter -- or at least an increase in attention paid to them by the media because of the homeless squatters' forced exposure to the winter cold. By Monday, children in Dobsonville were reported to be coming down with bronchitis.

Dobsonville women, using a startling new form of protest, had tried to embarrass the police into stopping Thursday's demolition by stripping to the waist and dancing in front of the bulldozers. But the tactic, a picture of which appeared prominently on the front page of the Star, Johannesburg's principal newspaper, failed to deter police for more than a few minutes.

By day's end, at least 12 people had been arrested for "illegal squatting and trespassing" and several hundred angry squatters were milling about the field wondering what to do.

One of them, Calvin Mukondeli, was so furious he could hardly talk. He had just paid 500 rand (about $195) as a down payment for tin siding, roof and wooden beams on a $330 shanty. Police had just bulldozed the half-built structure to the ground.

He pointed to a police van where two squatters were waiting to be driven away and said some considered arrest the best solution. At least the two men would have a place to sleep that night.

Like many squatters in Dobsonville, Mukondeli found himself out in the cold after his landlord, who had allowed him to put up a shack in his backyard (for a price, of course), changed his mind and ordered him out two weeks ago. In Mukondeli's case, it was to make way for a garage.

Some of the Dobsonville squatters tried to stick the pieces of their broken shacks back together again after dark. But at 2 a.m., the police returned, rounded up the squatters and set the shanties on fire. Over the weekend, the squatters managed to rebuild about 40 shacks. But on Monday morning, the police tore them down again.

Local activists such as Sam Shilowa, a spokesman for the Dobsonville branch of the Soweto Civil Association, have seized upon the issue and vowed to help the squatters defend themselves.

This emerging alliance between the homeless and politicians appears to reflect a new militancy within the black community since the legalization by President Frederik W. de Klerk in early February of groups opposed to South Africa's system of apartheid, or racial separation.

"It's the climate we are in," said Shilowa, who lives in a solid, four-room house in Dobsonville next to the field where the squatters set up camp June 28.

The African National Congress, South Africa's leading anti-apartheid group, "is talking about the redistribution of land -- but later on," Shilowa said. "People have been waiting since 1978 for land promised by the council here {in Dobsonville}. There are four {squatter} shacks behind every house here, and people are being exploited by their landlords. That's an issue that has to be addressed now."

Shilowa accused the government of "talking peace but declaring war on the people" by deciding to remove squatters all around Johannesburg.

The United Democratic Front, an umbrella coalition of anti-apartheid groups, announced in Dobsonville on Monday that it would launch a campaign next month to get homeless people to occupy vacant lands nationwide, including those located in areas designated for whites only.

On the same day, the minister for provincial affairs, Hernus Kriel, said the homeless were being used as "political tools" by black activists and that the government intended to prevent unauthorized squatting.