Check out CNN affiliate WPVI-TV in Philadelphia for the latest updates.
Los Angeles (CNN) -- Police in Los Angeles and Philadelphia dismantled tents and arrested Occupy protesters who refused to leave city property early Wednesday.
Los Angeles police moved in at 12:30 a.m. About an hour later, the City Hall lawn was cleared and closed for cleanup. About 200 people were arrested in the operation, which utilized some 1,400 officers, said Police Chief Charlie Beck.
Police described the operation as fairly peaceful, and Mayor Antonio Villaraigosa early Wednesday praised officers' professionalism.
The Los Angeles encampment, which has been in place for some 60 days, had become the largest one remaining after police raided New York's Zuccotti Park on November 15 and dismantled the nearly two-month-old camp there.
In Philadelphia, 52 people were arrested, said police spokeswoman Christine O'Brien.
The evictions at Dilworth Plaza came about 1 a.m., Philadelphia Mayor Michael Nutter said in a statement.
Scuffles broke out after police ordered some protesters to clear the street, CNN affiliate WPVI said.
O'Brien said police remained at the scene Wednesday, and the plaza was being cleaned. WPVI reported several streets were closed until further notice.
Four people were injured, Nutter said in the written statement. One police officer sustained a shoulder injury, another cut his hand while making arrests, and a third cut his leg while taking down a tent. A protester was injured when a police horse stepped on her toe, O'Brien said, and was taken to a hospital.
On Monday, Nutter gave protesters camped at Dilworth Plaza a 48-hour notice to vacate the site, citing a pending construction project.
With the Los Angeles and Philadelphia evictions, Occupy encampments remained in a handful of cities including San Francisco; Asheville, North Carolina; Oklahoma City; and Washington, according to media reports and websites set up by the movement in some cities.
In Los Angeles, officers in riot gear and armed with batons closed off streets around City Hall, using bullhorns to warn scores of agitated Occupy LA protesters to disperse.
"This has been declared to be an unlawful assembly. You have seven minutes to gather your belongings and decide to leave," one officer said.
During the raid, more than a dozen protesters sat in a tight circle in the middle of the park with their arms linked. Some cried. Some wore masks.
A white police truck drove through the center of the park, announcing orders to disperse in English and Spanish.
Some campers left willingly. One carried a skateboard under one arm and what looked like a rolled-up sleeping bag in the other.
Officers were met with profanity but no violence.
"This is what a police state looks like!" some of the protesters chanted.
Villaraigosa said the police action was "a measured approach to enforcing the park closure."
On Sunday, he gave the group a 12:01 a.m. Monday deadline to take down their camp, saying "an encampment on City Hall grounds is simply not sustainable indefinitely."
But the protesters held their ground. Four people were arrested, but police pulled back.
The demonstrators sought a federal court injunction to block their removal, claiming that enforcement of the city's "anti-camping" provision is left up to the whim of the police.
The City Council has "expressly affirmed" that the demonstrators are within their First Amendment rights, their complaint said, and Villaraigosa, in ordering them to leave, overstepped his authority.
The case remained pending Wednesday.
In announcing the Wednesday police raid, the mayor said the park will be closed, and then reopened to "all Angelenos to exercise their First Amendment rights."
The protesters are welcome back, but they cannot camp out -- the same arrangement as at New York's Zuccotti Park.
The Occupy Wall Street movement that began in New York in September has spread across major cities worldwide as a call to action against the unequal distribution of wealth.
In recent weeks, cities have begun clearing encampments, citing economic, health and public safety concerns.
While only a handful of protesters remained at Zuccotti Park, hundreds meet on a regular basis in the atrium of a building on Wall Street.
One problem faced by the Occupy movement is that its tactics "are really costly to themselves," meaning its members, said Michael Heaney, a University of Michigan professor who studies social movements. "Basically what they've done is, they've built a movement around a tactic that requires a high level of commitment on the part of its members" in terms of arrests and legal action or perhaps having their property confiscated.
That tactic -- camping in public spaces -- can succeed for a while, he said, "but the police will inevitably crack down."
In order to survive, he said, the Occupy movement needs to adopt some other tactics in order to change the system through internal pressure, not just external pressure, he said. Those might include lobbying, for instance.
The civil rights movement, he said, used tactics such as marches and sit-ins, but also formulated a legal strategy and lobbied for the Civil Rights Act.
But in the Occupy movement, it's precisely the current tactic that has inspired people, he said, making it tough for the movement to reorient itself. In addition, members have ideological reasons to reject alternative tactics, he said.
"The people that are at the heart of the Occupy movement are more committed to their way of organizing than they are to achieving the policy goals they say they support," Heaney said. "... They care more about doing social action in the way they want to do it," meaning a non-hierarchical, "leaderless" approach.
In addition, he noted, policy change in the United States can take decades -- allowing gays and lesbians to serve in the military, for example. "In order to achieve policy change, you need institutions and interests committed over a period of several decades to bringing about those changes."
Still, the Occupy movement has been "the most successful anarchist movement in history," he said, and is able to organize people effectively. But, he said, it's hard to see a clear path to its next stage.
CNN Radio's Steve Kastenbaum and CNN's Paul Vercammen and Sandra Endo contributed to this report.