An attacker with a knife killed three people and seriously wounded at least five late on Friday at a festival in the western German city of Solingen, authorities said.
Witnesses alerted police shortly after 9:30 p.m. local time to an unknown perpetrator who had wounded several people indiscriminately with a knife on a central square. Police said have no one in custody and had little information on the man.
They said they believe the stabbings were carried out by a lone attacker.
One of the festival organizers, Philipp Müller, appeared on stage and asked festivalgoers to "go calmly; please keep your eyes open, because unfortunately the perpetrator hasn't been caught."
He said many people had been wounded by "a knifeman."
At least one helicopter was seen in the air, while many police and emergency vehicles with flashing blue lights were on the road and several streets were closed off.
Police put the number of seriously injured at five. The region's top security official, Herbert Reul, gave a figure of six as he visited the scene in the early hours of Saturday.
"None of us knows why" the attack took place, said Reul, who is the interior minister of North Rhine-Westphalia state.
"I can't say anything about the motive now" and it isn't clear who the assailant was, he said, adding that the attacker had left 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.
