Police are looking for a suspect who assaulted a man near the Civic Center BART station this afternoon.
Witnesses at the scene said the two men were in an argument on the sidewalk on Market Street near Hyde Street shortly before 3:30 p.m.
When the two men turned to walk away, one hit the other in the back of the head.
The victim was lying on the sidewalk when police arrived and bleeding from the back of the head. He was conscious when paramedics arrived and loaded him into an ambulance.
Witnesses said the suspect ran away west on Market Street and police went looking for him.