The San Francisco Fire Department responded to reports of smoke in City Hall tonight, a dispatcher said.

Firefighters were called to City Hall at 9:26 p.m. on reports of smoke and arrived to find that the building's sprinkler system had been activated. The smoke had come from a problem with an electrical panel, according to fire officials, and PG&E crews were called to the scene.

Minimal fire units remain there tonight. Any fire was handled by the sprinklers, according to the Fire Department.