PHILADELPHIA (Reuters) - Anti-Wall Street activists in Philadelphia vacated their camp early on Wednesday after police moved in and warned protesters they faced arrest unless they cleared out of their downtown compound, police said.

"They walked away," police spokesman Lieutenant Ray Evers said, adding that about 100 protesters had been in the Occupy Philadelphia camp when police arrived. Police said no arrests were made.

Outside the plaza near City Hall, scores of protesters chanted: "Who do you protect? Who do you serve?" as officers milled about nearby.

(Reporting by Dave Warner; Editing by Steve Gorman)