Eight were injured, five of them seriously, the police said in a statement early on Saturday.
"Both victims and witnesses are currently being questioned. The police are currently searching for the perpetrator with a large team," police said.
The incident occurred around 9:40 p.m. (1940 GMT) on Friday, when the man attacked multiple people with a knife, the police said, adding that the motive remained unclear.
"The perpetrator must be quickly caught and punished to the fullest extent of the law," German Chancellor Olaf Scholz
said in a post on X.
Germany's interior minister, Nancy Faeser, said security authorities were doing everything they could to catch the person and investigate the background to the attack, which occurred at the Fronhof, a market square in Solingen where live bands were playing. It was during a festival marking the 650th anniversary of the city in the state of North Rhine-Westphalia, which borders the Netherlands.
Police had cordoned off the square on Saturday, and passers-by placed candles and flowers outside the barricades.
"We are full of shock and grief," Solingen Mayor Tim-Oliver Kurzbach told journalists on Saturday morning.
The German musician who goes by the name Topic said he was playing on a nearby stage when the incident occurred. He was told about what happened but was asked to continue "to avoid causing a mass panic attack", he posted on Instagram.
He was eventually told to stop, and "since the attacker was still on the run, we hid in a nearby store while police helicopters circled above us," Topic wrote.
Authorities cancelled the remainder of the weekend festival.
Sourrce:Reuters