German authorities are investigating a Saudi doctor, arrested as the suspected driver of the car, with Der Spiegel magazine reporting he had sympathies with the far-right Alternative for Germany (AfD) party.
Over 60 people were injured, some of them seriously, when a vehicle drove through crowds gathered at a market in the central city, local officials said. A young child was among the dead.
Police said they arrested a 50-year-old from Saudi Arabia who has been living in Germany for almost two decades. Police did not name the man and were not immediately available to comment on the reported rise in the death toll.
The man worked as a doctor in a nearby town, local officials said. Police searched his home overnight.
A Saudi source told Reuters that Saudi Arabia had warned German authorities about the attacker after he posted extremist views on his personal X account that threatened peace and security.
Der Spiegel reported that the suspect had sympathised with the AfD. The magazine did not say where it got the information.
German Chancellor Olaf Scholz is set to visit Magdeburg later on Saturday, following the tragic events at the city's Christmas market.
Leaders worldwide have offered their condolences to the victims of the attack.
Polish President Andrzej Duda expressed his sympathies in a Facebook post, saying, “Tragic news from Germany. I am shocked by the brutal attack at the Christmas Market in Magdeburg. My thoughts and prayers are with the families of the victims and those injured.”
French President Emmanuel Macron said on the X platform: “Deeply shocked by the horror that has struck the Christmas market in Magdeburg, Germany, this evening. My thoughts are with the victims, the injured and their families. France shares the grief of the German people and expresses its full solidarity.”
Migration debate
The attack comes at a time of heightened debate over migration and security in Germany, which is gearing up for a snap election on February 23.
The AfD, currently polling in second place behind the conservative opposition, has led calls for a crackdown on migration to the country.
AfD chancellor candidate Alice Weidel condemned the attack and said on X, "The pictures from Magdeburg are shocking! My thoughts are with the bereaved and injured. When will this madness come to an end?"