NEW YORK—The overnight police raids in Philadelphia and Los Angeles that dismantled two of the nation's biggest Occupy Wall Street encampments leave just a few major "occupations" still going on around the U.S. But activists are already changing tactics and warning of a winter of discontent, with rallies and marches every week.

The camps may bloom again in the spring, organizers said, and next summer could bring huge demonstrations at the Republican and Democratic conventions, when the whole world is watching. But for now they are promoting dozens of smaller actions, such as picketing the president in New York and staging sit-ins at homes marked for foreclosure.

"We intend to use this for what it is -- basically six months to get our feet underneath us, to get strong," said Phil Striegel, a community activist in San Francisco.

On Wednesday, masked sanitation workers hauled away 25 tons of debris from the lawns around Los Angeles City Hall after police raided the protesters' camp in the middle of the night and arrested more than 300 people. In Philadelphia, dozens of police patrolled a plaza outside City Hall after sweeping it of demonstrators and arresting 50.

In the past few weeks, police broke up encampments in such cities as Portland, Ore., Oakland, Calif., and New York, where the sit-down protests against social inequality and corporate excesses began in mid-September.

Demonstrators are still at it in places like Boston and Washington, which each had encampments of about 100 tents Wednesday. Dozens of protesters are fighting eviction from a community college campus in Seattle

While some observers wondered whether the movement would wither without ground on which to make its stand, many protesters refused to concede defeat.

Protesters in Philadelphia marched from the city's well-to-do Rittenhouse Square to police headquarters Wednesday afternoon and also called for a "victory march" for Friday or Saturday.

"Occupy Philly is alive and well," said Katonya Mosley, a member of the group's legal collective. She said members have been communicating via list serves, text messages and email and planned to continue meeting in cafes and other spaces. Local groups have also offered to donate space for the protesters to continue meeting, Mosley said.

While one faction received a permit for a scaled-down protest across the street, she said, Occupy Philadelphia as a whole hasn't decided whether to go that route. The city has said any new permit would include a ban on camping