German police have arrested a suspect in connection to the stabbing at a gym in the western city of Duisburg, the public prosecutor for Germany's state of North-Rhine Westphalia confirmed on Sunday.

Four people were injured on Tuesday when a man went on a rampage in a fitness studio in Duisburg's old town, using a "stabbing or cutting" weapon.

Police arrested the 27-year-old suspect in his apartment in Duisburg on Saturday evening, a police spokesperson said. The public prosecutor's office confirmed that the suspect has Syrian citizenship.

Duisburg public prosecutor Jill Mc Culler said that police had been looking for the suspect since Friday after inspecting photos from a security camera.

The suspect will be brought before a magistrate's court on Monday, she added.

According to the current state of the investigation, a 21-year-old man was the apparent main target of Tuesday's attack. According to the public prosecutor, he was still in a life-or-death situation on Saturday.

Of the three other victims, two 24-year-olds were still in the hospital, but their statuses had stabilized. A 32-year-old had already been released from the hospital.

Authorities had offered a €2,000 ($2,200) reward for any information leading to an arrest.

ab/dj (AFP, dpa, AP)