Police were called to a road next to Telegraph Hill park late on Saturday night after reports of fireworks being thrown at pedestrians.
Police arrived at Kitto Road, which is next to the park, after more than six people called in to report dangerous behaviour around 11pm by a large group of teenagers on the road, which involved them throwing fireworks at other groups and pedestrians on the street.
Eyewitness and local resident Emmanuel Curon said: “There were at least 30 or 40 teenagers throwing fireworks at each other in hysterics just outside of the park, we walked past very quickly as me and my friends felt very unsafe, people were screaming and running.
“I couldn’t clearly see who was throwing the fireworks, although I think they were definitely aiming at people, specifically large groups.”
Kitto road was closed till early on Sunday morning due to the incident.
An officer on the scene said: “No one has been seriously harmed by the fireworks as far as we know, although someone has hit their head during the incident. There is blood on the floor which we are examining.”
The scene was cordoned off with police tape and was being guarded for several hours.