The German capital's police force said on Twitter that the perpetrators had fled the scene and that an investigation into the incident was already underway.
German news agency dpa reported that three of the injured had made their own way to the hospital while armed police were seen around the Tempodrom hall, a multi-purpose event venue in the Kreuzberg district of the German capital.
The arena was cordoned off following the shooting, which occurred at approximately 10.50 p.m. local time (2150 UTC/GMT). The police were said to be looking for several suspects, Deutsche Welle reported.