(CNN) A masked gunman stormed a German cinema Thursday afternoon, taking hostages before he was killed by police, officials said.
The rifle-wielding man entered the cinema in Viernheim, near Frankfurt in western Germany, shortly before 3 p.m. local time, Hesse Interior Minister Peter Beuth said.
Police received reports of four shots fired.
German public TV initially said 25 people were injured, but it wasn't clear if they were shot or hurt in other ways.
After the ordeal ended, a Viernheim police spokesman told CNN that no one was injured by gunfire aside from the attacker.
The U.S. Embassy in Germany said officials are looking into the possibility that tear gas might have caused some of the injuries, spokeswoman Jackie McKennan said.
At one point, the assailant took hostages, but it's unclear why.
"There were hostages in the vicinity of the individual. It was at this point that he was fatally shot by special forces," Beuth said. "I have no knowledge that anyone else was harmed."
The cinema is part of a major shopping center called Rhein Neckar Zentrum Viernheim. The complex, with more than 100 businesses, hosts 20,000 visitors daily, according to its website.
An employee at Coyote Café Viernheim, just across from the cinema, said about 50 to 100 officers rushed to the scene.
"Our café went into lockdown. We brought all of our customers out of the back door," said the employee, who asked not to be named.
"This is something very unusual for our town. I've never seen anything like that. I never want to see anything like that again."
Late Thursday afternoon, the shopping complex announced the police operation was over.
"At this moment in time we have no information on injured persons," the shopping center said on its Facebook page. "The driveway is still blocked. We will keep you updated on new developments. "
The motive for Thursday's attack remains unclear, but German police said there's no indication the incident was terror-related.
Prior to the attack, police had repeatedly warned that Germany could be targeted by ISIS.
Germany absorbed more than 1 million refugees last year, and there have been concerns about the possibility of ISIS cells in the country.