A woman has been killed and other people badly injured after a car drove into a crowd on a busy Berlin street.
Police say the driver, a 29-year-old man, was detained by passers-by and arrested at the scene.
Emergency officials said it was unclear whether the incident, which happened shortly before 10:30 local time (08:30 GMT), was intentional or an accident.
The incident took place in the heart of western Berlin, on one of its busiest shopping streets.
The woman who died has been identified as a schoolteacher who was on a trip with a class of teenagers from the central state of Hesse. "There are seriously injured people among the more than a dozen injured," police spokesperson Thilo Cablitz said.
The driver has dual German and Armenian citizenship and lives in Berlin. Police said they could not confirm reports that he had left a note in his car.
Witnesses described seeing a silver Renault Clio veering into a crowd of people on the pavement near Berlin's busy Kurfürstendamm shopping avenue, before driving back on to the road and crashing into a shop window.
Some 130 emergency workers went to the scene and a body lay in the middle of the road, covered in blankets.
It happened opposite Breitscheidplatz, where 12 people were killed in a terrorist attack in 2016 when a truck was deliberately driven into a crowd of people at a Christmas market.
Berlin Mayor Franziska Giffey said it was too early to know if the area had been chosen deliberately, but she said: "It's a situation where you think, for God's sake, not again!"
The actor John Barrowman tweeted that he was nearby when the incident took place and in a video posted from the scene said the car had repeatedly mounted the footpath before crashing into the storefront.
"The police presence is unbelievable. They are clearing out the area," the actor said. "There's helicopters coming in now to airlift people."