German police launched an investigation Saturday into a group of about 100 masked protesters who carried out acts of vandalism in the east German city of Leipzig, injuring several police officers, according to dpa. Police are not ruling out the possibility that the riot late on Friday, which police chief Bernd Merbitz described as an "extreme act of violence," was linked to protests against the G7 summit taking place in southern Germany over the weekend. The protesters built barricades of tires in the city centre, and used stones and molotov cocktails to attack vehicles and buildings including the US consulate and a court house. Police dispersed the mob and one protester was arrested. There have been several similar protests in Leipzig in recent months. Police suspect involvement of left-wing extremists.