(Reuters) - Demonstrators in Oakland, California, broke store windows and vandalized a public Christmas tree during a march protesting police shootings, media reports said.

Vandals who were among about 50 largely peaceful marchers broke store windows in downtown Oakland late on Thursday, looted a liquor store and pulled ornaments and lights off the Christmas tree, the SFGate news website reported.

An Oakland police spokesman said there were no arrests but had no other details about the protest.

The demonstration followed weeks of marches around the San Francisco area after grand juries in Missouri and New York declined to indict white police officers in the killings of unarmed black men.

The San Francisco-area protests have included some looting, rock throwing and property damage. Scores of protesters have been arrested.

(Reporting by Ian Simpson; Editing by Bill Trott)