Police said only that he was injured during the police operation to free the woman. Police said the situation was considered "under control" and there was no immediate suspicion of a link to terrorism.
The hostage situation broke out earlier in the day near the main railway station in Cologne.
Following a hours-long standoff, German police have finally apprehended an assailant who took hostage a woman near Cologne central station.
"We have made contact with the attacker", he said, adding that police were trying to clarify "what does this man want, what are his demands, and is he armed?"
Police officer Christoph Schulte told Associated Press that the incident appears to have started at 12.45pm inside the station. Breslauer Platz square that's located behind the station was also closed.
Hostage held at Cologne main train station
There are unconfirmed reports that some shots were fired.
It is not yet clear why the man took the woman hostage.
German railroad operator Deutsche Bahn said that all train traffic was shut down.
Special police operate outside the Cologne, western Germany, train station Monday, Oct. 15, 2018.
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