A car has ploughed through a pedestrian area in the western city of Trier at lunchtime, killing several people including a baby, police say.
The driver, a 51-year-old local man, has been arrested. The circumstances of the incident are still not clear.
Witnesses said people screamed in panic and some were thrown in the air by an SUV travelling at high speed.
The city’s mayor described the scene as “horrible” and said up to 15 people had been injured, some of them seriously.
The incident happened at around 13:45 local time (12:45 GMT) in Trier’s Fleischstrasse pedestrianised street, near the city’s famous Roman gate, the Porta Nigra.
A Christmas market that is usually held in the area was cancelled this year due to the Covid-19 pandemic, but shops were open. The streets have been cordoned off.
The suspect drove for 1km (0.62 mile) before being stopped by a police car, Trier police spokesman Karl-Peter Jochem said. Footage posted on social media appeared to show the presumed driver being held by several officers next to the damaged car.
Police were questioning the suspect, who was alone, and the danger “was over”, Mr Jochem said. “As to the man’s motive, we can’t say anything yet,” he added.
Mayor Wolfram Leibe told a news conference: “We [had] a driver who ran amok in the city… I just walked through the city centre and it was just horrible. There is a trainer lying on the ground, and the girl it belongs to is dead.”
Police said “several people” had been killed having earlier put the death toll at two.
Chancellor Angela Merkel said in a statement: “The news from Trier is very sad. My sympathy goes to the relatives of people who were torn from their lives so suddenly and forcibly. I also think of those who have suffered severe injuries and I wish them much strength.”
The incident has shocked Trier, a medieval city of around 110,000 people and 720km west of Berlin, near the border with Luxembourg. Police have told people not to share pictures and footage of the incident on social media.
Security in pedestrian zones across Germany was tightened after an Islamist militant drove a hijacked truck into a Christmas market in Berlin in 2016, killing 12 people and injuring dozens of others. He was shot dead by Italian police four days later.