A suspected hostage-taking prompted the evacuation of a train station in the western German city of Cologne on Monday, but police said they could not confirm reports that shots had been fired.
"We assume that a hostage has been taken, either at McDonald's or at a nearby pharmacy," a police spokeswoman said. "A woman is probably being held but we don't have any further details."
German magazine Focus had earlier reported that several shots appeared to have been fired at Cologne's main train station, which is next to the city's landmark cathedral, a major tourist attraction.
"We currently cannot confirm there have been shots or deaths," Cologne police said on Twitter.
Germany is on high alert for militant attacks, almost two years after a Tunisian Islamist rammed a hijacked truck into a Christmas market in central Berlin, killing 11 people as well as the driver.
A police spokesman told German broadcaster n-tv that police were in contact with the hostage-taker, who was inside a pharmacy at the train station, but said it was unclear whether he was armed and what his motives were.
German state-owned rail operator Deutsche Bahn warned that rail traffic was being delayed by the closure of the station.
Images taken outside the station showed the steps of Cologne's cathedral were crowded with travellers carrying suitcases.