A nine-week-old baby was among the five victims killed when a car tore through a pedestrian shopping street in the southwestern German city of Trier, said police, after arresting the driver. 

Three women, aged 25, 52 and 73, were killed. The 45-year-old father of the baby was also killed, while his wife and one-year-old son were injured and admitted to hospital. 

Prosecutor Peter Fritzen said the driver, a 51-year-old Trier native, appeared to be suffering from "psychiatric problems" and was under the influence of alcohol during the incident, in which up to 15 other people were also injured. 

Witnesses also described seeing people being flung into the air as the car struck them. 

According to police, there were "no indications of a political motive" after questioning the suspect and Fritzen said prosecutors were considering requesting for him to be placed in psychiatric care. 

"I think this is Trier's darkest day since World War II," he added. 

Malu Dreyer, the premier of the state of Rhineland-Palatinate, where Trier is located, expressed his shock that a baby was among those killed by the driver's "insane act" and shared her condolences with all the affected families. 

The mother of the baby is being treated in hospital for injuries sustained in the incident. 

The incident started at around 12:50 p.m. GMT and ended within four minutes of the first emergency calls arriving, with police intercepting the driver after he turned off a main shopping street. 

Police said he had plowed through the streets for between 600 meters and a kilometer, leaving behind a trail of destruction. 

Officers sealed off the area and cleared people from the center of the city, which has a population of about 110,000 people. Smartphone footage recorded by an eyewitness in the area at the time showed the arrest of the driver, handcuffed and lying face down on the street. He was pinned down by several officers next to the damaged vehicle. 

In the evening, the cathedral bells were rung and a memorial service was held for the victims.

Germany's Chancellor Angela Merkel voiced her "great sadness" and said her thoughts were with the relatives of those who were "so suddenly and violently ripped from their lives." Merkel also said that her thoughts were with the injured in a message shared by her spokesman. 

Early footage from the scene showed stunned shoppers gathering outside stores adorned with Christmas decorations as sirens could be heard blaring in the distance. Broken glass and debris from stalls and outdoor displays were strewn along the cobbled streets.

At the time of the incident, the mayor of Trier confirmed to public broadcaster SWR: "We have a driver on a rampage in the city. We have two dead that we are certain of and up to 15 injured, some of them, with the most severe injuries." 

He added: "Our first task now is to make people safe." 

Locals were asked to avoid the city center, especially the pedestrianized zone where the incident took place. 

The city center was cordoned off and helicopters were circling overhead, according to local reporters. Parents were also asked to pick up their children from school early.

Trier is a picturesque city near the border with Luxembourg, and it is often called Germany's oldest city because it traces its history back to the Roman Empire. It is also the birthplace of philosopher and political theorist Karl Marx. 

Although Germany is fighting a second coronavirus wave that has forced restaurants, bars, sports and cultural centers to close, retailers have been able to stay open and many people were out shopping when the incident happened. 

"It's lucky that the Christmas market has been canceled because of corona, or it could have been much worse," witness Frederic Fries said to Welt TV.

Germany has suffered a spate of similar incidents in recent history.

In 2016, a truck drove into a crowd at a Berlin Christmas market, killing 12 people. In April 2018, a German man plowed his van into people seated outside a restaurant in the city of Muenster, killing five before shooting himself dead. Investigators confirmed that he had mental health problems. 

A German man also injured eight people in January 2019, when he drove into crowds on New Year's Eve in the western cities of Bottrop and Essen. He was later taken into psychiatric care.