Witnesses alerted police to an early-morning attack Thursday, in which a woman was reportedly suffered injuries to her head.

Police say that witnesses heard a woman screaming for help at 6:45 Thursday morning, and alerted the San Francisco Police Department to the disturbance.

Officers who arrived on the scene at the 2000 block of Bryant Street, which is between 18th and 19th Streets, discovered a woman who they say was "bleeding from the head."

According to the SFPD, the woman had been attacked by a male suspect of unknown age. She was transported to an area hospital for injuries police say are not life threatening.

The suspect, police say, remains at large, and no arrests have been made. If you know anything about the case, police ask that you call SFPD's Anonymous Tip Line at 415-575-4444 or text a tip to TIP411 with SFPD at the beginning of the message.