Five people are dead, including a baby, and up to 15 seriously injured after a car drove into pedestrians in the German city of Trier.
The city's Mayor, Wolfram Leibe, said the driver had gone on a "rampage" in a pedestrian-only shopping area about 1.45pm on Tuesday.
A German man, 51, from the Trier district has been arrested and the car impounded by police.
Karl-Peter Jochem, a Trier police spokesman, said the suspect was being questioned and the danger was over.
The public prosecutor said later that the suspect was drunk at the wheel, adding there was no indications of a religious motive to the attack.
The prosecutor said the suspect had no prior convictions.
But the Interior Minister of Rhineland-Palatinate said the course the driver took indicates it was done on purpose.
Mr Leibe said that a nine-month-old baby and a woman aged 72 were among the dead.
A witness said a grey Range Rover was driving at high speed and people had been thrown into the air, local newspaper Trierischer Volksfreund reported.
It said the city centre had been cordoned off and helicopters were circling overhead.
Mr Leibe said the driver had gone on "a rampage".
"We had a driver who ran amok in the city," he told broadcaster SWR. "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."
He told N-TV: “I don’t want to speculate, but all of us are asking ourselves, what drives a person to do something like this?
"Of course, I don’t have an answer to this question.”
Chancellor Angela Merkel's spokesman, Steffen Seibert, called the incident shocking.
"Our thoughts are with the relatives of the victims, the many injured and all those who are helping to care for those affected," Mr Seibert said.
Footage from the scene showed police vans and other emergency vehicles parked on a wide shopping street.
Rhineland-Palatinate Governor Malu Dreyer, who is from Trier, and condemned the incident as a “brutal act".
“It was a really, really terrible day for my home town,” Ms Dreyer said after visiting the scene.
Shoppers huddled outside stores festooned with Christmas decorations as sirens blared in the distance.
Although the incident did not appear to have terrorist motives, it brought back memories of the 2016 lorry rampage at a Berlin Christmas market, which killed 12 people.
The driver, a failed Tunisian asylum seeker, was a supporter of ISIS.
In August 2019, six people were injured in motorway accidents in Berlin in what prosecutors described as a suspected terrorist attack.
Trier is about 200 kilometres west of Frankfurt, near the border with Luxembourg.
The city of about 110,000 people is known for its Roman gate, the Porta Nigra, which is near the scene of the crash, and as the birthplace of Karl Marx.