A 9-week-old baby and her 45-year-old father, as well as a 73-year-old woman are known to be among the fatalities. The other dead are women aged 25 and 52.

Speaking to the press at 3.20pm, an emotional Wolfram Liebe (SPD), the mayor of Trier, and emergency services representatives said they were not yet prepared to give details of the number of fatalities and injured, but they spoke of "several" dead.

The suspect is a 51-year-old male, who is a German citizen from Trier. It appears that the car that ploughed into the pedestrians was a Range Rover. 

Police spokesman Karl-Peter Jochem told Bild in a live interview at 3.45pm, that the car, an SUV, drove around 1km through pedestrian zone.  Jochem spoke of several seriously injured, and thinks the figure will rise above the current official number of 10, and also of traumatised witnesses. The city centre was sealed off as police forensics teams secured the scene.

Luxembourg prime minister Xavier Bettel expressed his sympathy with the victims and their families, and the city of Trier, via Twitter. “I am deeply shocked and dismayed by the terrible news from Trier. My thoughts are with the victims and the many injured and their relatives. At this difficult moment, Luxembourg is firmly at the side of our neighbours and friends.”

Grand Duke Henri in a letter to Germany's president Frank-Walter Steinmeier wrote: "Our thoughts and sympathy are with the victims and their relatives," saying he and the grand duchess had been "deeply upset" by the incident. "We assure Germany of our full solidarity and support in these difficult times," Luxembourg's monarch said.

It appears the driver drove into Brotstrasse, a pedestrian shopping street, from Konstantinstrasse. He then sped along the pedestrian zone, driving through the main market square, which would usually have been host to the city’s Christmas market. The car then drove on to the Porta Nigra via Simeonstrasse before turning into Christophstrasse where he was stopped by police vehicles.

The driver, who was alone in the vehicle, was arrested after a short struggle. It took just four minutes from the time the emergency services were first alerted to the time of the arrest.

While the authorities in Trier have not speculated about the motives of the perpetrator, Luxembourg City has announced it will be securing its pedestrian zones with a system of barriers as of Wednesday evening.

Mayor Lydie Polfer also added her condolences to the victims and their families in Trier. She said the City of Luxembourg would extend unreserved support to its neighbour in Germany.

At a 7pm press conference, the mayor of Trier, Wolfram Liebe, thanked the 700 emergency service personnel who sprang into action on Tuesday afternoon. A make-shift shrine at the Porta Nigra will allow well-wishers to pay tribute to the dead and injured.

Liebe said it was the “darkest day for Trier since WWII.”

The suspect had apparently been living in his car rather than in his apartment over the past couple of days. Reports suggest he was under the influence of alcohol at the time of his arrest.