An early-morning scuffle in the western German city of Cologne left a man seriously wounded Monday, and police have taken some bar patrons in for questioning.

A number of callers reported a street disturbance involving several people in downtown Cologne shortly before 4:00 local time (0200 GMT), police said in a statement.

Officers found shattered glass and a substance that looked like blood at the scene. They also found several bullet casings nearby. Investigators are working to determine if the casings are linked to the incident, police said.

Authorities said they had no indication the skirmish was terror-related.

Witnesses reported seeing several vehicles hastily leaving the street where the scuffle happened, police said. Officers stopped an SUV driven by a 34-year-old man, who was taken to a hospital with stabbing and head injuries.

Shortly afterward, police took several people from a bar in another part of the city in for questioning.