Solingen, Germany — An attacker with a knife murdered three people and critically injured at least five others late Friday at a festival in Solingen, western Germany, according to authorities. Witnesses called authorities shortly after 9:30 p.m. local time about an unknown criminal who had indiscriminately wounded multiple persons with a knife in a central square. Police stated they had no one in custody and little information about the individual. They stated they suspect the stabbings were committed by a single perpetrator. Philipp Müller, one of the festival’s organizers, stepped on stage and encouraged attendees to “go calmly; please keep your eyes open, because unfortunately, the perpetrator hasn’t been caught.” He said that numerous individuals had been injured by “a knifeman.”

At least one helicopter was spotted in the sky, while numerous police and emergency cars with flashing blue lights were on the road, and several streets were closed. Police said five people were critically injured. Herbert Reul, the region’s chief security official, gave the figure of six when he visited the scene in the early hours of Saturday. “None of us knows why” the incident occurred, said Reul, North Rhine-Westphalia’s interior minister. “I can’t say anything about the motive now” because it’s unclear who the assailant was, he added, adding that the attacker had fled the scene “relatively quickly.”

The “Festival of Diversity,” marking the city’s 650th anniversary, began on Friday and was supposed to run through Sunday, with several stages in central streets offering attractions such as live music, cabaret and acrobatics.

The city canceled the rest of the festival after the attack. Solingen has about 160,000 residents and is near Cologne and Duesseldorf.

There has been concern about an increase in knife violence in Germany recently.

In May, a knife attack by an Afghan immigrant on members of a group that describes itself as opposing “political Islam” left a police officer dead.

Germany’s top security official, Interior Minister Nancy Faeser, this month proposed toughening weapons laws to allow only knives with a blade measuring up to 6 centimeters to be carried in public, rather than the length of 12 centimeters that is allowed now.