Authorities began Thursday dismantling a notorious homeless camp known as "The Jungle" in the heart of California's affluent Silicon Valley.
Municipal workers in white overalls and face masks moved into the camp along a creek in San Jose, where some 300 people live in tents and other makeshift lodging.
The encampment, only a few minutes away from the city's downtown district, is home to people forced out of an overheating rental market as lucrative tech companies moved in in recent years.
"We have been rehousing for the last 18 months," San Jose city spokesman David Vossbrink told AFP, saying they had found places for some 140 people in shelters, with some in hotels and motels.
Some 60 other people had received offers of rent subsidies but have not yet found somewhere to live, he added.
The operation to close down the camp will last two or three weeks, and will include putting up a reinforced fence to prevent anyone coming back and settling in again.
But the spokesman admitted that those forced to leave the "Jungle" could not all expect to be housed by the city, which has budgeted nearly $10 million over three years for homeless.
San Jose is counting on a refuge set to open for the winter to house some 200 people of Santa Clara County's estimated 5,000-7,000 homeless, he said.
The city, with its population of around one million, has one of America's highest proportions of homeless people.
The spokesman attributed the problem to various factors, including the 2008 global financial crisis, exorbitant rents fueled by the tech boom, and the scarcity of unskilled jobs.
Vossbrink said the "Jungle" had to be cleared because it posed security, public health and pollution problems, and because of looming winter temperatures. "It's becoming urgent," he said.
But some activists are protesting the operation.
Scott Wagers, a pastor who heads a homeless support association, said the camp developed over the last two years, after the clearance of another slum in San Jose.
"The people are just going to move to another place that will become another jungle," he said.