Police say search under way for unknown assailant after attack on festival-goers that injured eight people.

Police in Germany are searching for an unknown suspect behind a mass stabbing at a festival in the western city of Solingen in which three people were killed.

Eight people were injured, five of them seriously, police said on Saturday as thousands had gathered at a central square for celebrations to mark Solingen’s 650th anniversary. The dead included one woman and two men.

“Both victims and witnesses were currently being questioned,” police in the nearby city of Dusseldorf said in a statement early on Saturday, adding that “a large contingent” of officers were searching for the perpetrator.

At about 9:40pm (19:40 GMT) on Friday, an unidentified man attacked multiple people with a knife, police said.

Police said the attack occurred at the “Festival of Diversity” in Solingen, which is located in North Rhine-Westphalia state, Germany’s most populous and bordering the Netherlands.

The events were supposed to run through Sunday, with several stages in central streets offering attractions such as live music, cabaret and acrobatics. Solingen has about 160,000 residents and is located near the bigger cities of Cologne and Dusseldorf.

Police on Saturday warned residents who observe anything suspicious not to act on their own initiative but call the police emergency number.

“We currently have no clues as to his whereabouts,” said a police spokesman. There was also no description of the suspect, Germany’s DPA news agency reported.

The interior minister of North Rhine-Westphalia state, Herbert Reul, visited the scene early on Saturday, telling reporters it was a targetted attack on human life but declining to speculate on the motive.

Fatal stabbings and shootings in Germany are relatively uncommon.

Interior Minister Nancy Faeser recently proposed toughening weapons laws to allow only knives with a blade measuring up to 6cm (2.4 inches) to be carried in public, rather than the currently allowed length of 12cm (4.7 inches).

“It tears my heart apart that there was an attack on our city. I have tears in my eyes when I think of those we have lost,” Solingen Mayor Tim-Oliver Kurzbach said in a statement. “I pray for all those who are still fighting for their lives.”

“This evening, we are all facing shock, horror and great sadness in Solingen. We all wanted to celebrate our city’s anniversary together, and now we have to mourn dead and injured people,” Kurzbach wrote.