Four people including a nine-month-old baby were killed and up to 15 injured on Tuesday when a speeding auto ploughed into a pedestrian area in the western German city of Trier in what authorities said appeared to be a deliberate act.
The Premier of Rhineland-Palatinate, Malu Dreyer, expressed shock about the events in Trier, her hometown, in what she called "a awful day" for the city and the country.
German police in Trier where four people, including a young child, were killed by a lone driver. Leibe said. "Of course I don't have an answer to this question".
Malu Dreyer, premier of the state of Rhineland-Palatinate where Trier is located, said she was shocked that a baby was among those killed by the driver's "brutal act".
"It was a really, really bad day for my hometown", Mr Dreyer told reporters after visiting the scene.
Police gave an initial toll of at least two fatalities and several injured, but said the figures were likely to climb.
Firefighters at the scene of an incident in the southwestern German city of Trier.
Footage from the scene showed people outside a shop apparently helping someone on the ground lying among scattered debris.
But Trier Mayor Wolfram Leibe was quoted by regional broadcaster SWR as saying the driver had gone on "a rampage" that had caused at least two deaths and 15 injuries.
Officers sealed off the area and cleared people from the city centre. It was a sight of horror.
Rescue workers and onlookers stand near the scene after a vehicle drove into a pedestrian zone in the city of Trier in Germany, Tuesday, Dec 1, 2020.
Footage posted on social media appeared to show the presumed driver being held by several officers next to the damaged auto.
"I don't want to speculate, but all of us are asking ourselves ... what drives a person to do something like this?"
Police said the oldest victim was aged 73.
In a video posted by a local media outlet purportedly showing the arrest, police could be seen pinning a man down on the sidewalk next to a vehicle with Trier license plates.
Police subsequently arrested a 51-year-old German citizen and are investigating the circumstances around the incident, and whether there was any motive.
"My sympathy goes out to the relatives of those whose lives were ended so abruptly and violently", Merkel said, adding that she those who were injured and affected by the incident were also in her thoughts.