Berlin State Interior Minister Andreas Geisel said it was still unclear if it had been an attack or an accident.
German authorities are still undecided whether the driver of a Polish-registered articulated lorry deliberately ploughed into a busy Christmas market in Berlin, killing 12 people and injuring 45.
Berlin State Interior Minister Andreas Geisel said it was still unclear if it had been an attack or an accident.
However, there have been strong indications that the lorry driver might have had his vehicle hijacked.
A suspicious person was arrested nearby, police say, while what they describe as a passenger was found dead.
The market where the incident took place is close to the main shopping street in Berlin’s west
According to the DPA news agency, police believe the lorry drove 50-80 metres through the market area during the incident, which occurred at 20:14 local time.
AP Television footage showed a large Scania truck with its windshield smashed out on the sidewalk alongside the market, with several ambulances nearby. A Christmas tree with a gold star on top was toppled over in the street, and tree branches were crushed under the truck's tyres.
"The sequence of events points to either an accident or an attack," the interior minister said.
Late last month the US State Department issued a warning telling American citizens to exercise caution at "holiday festivals, events and outdoor markets".
The warning followed news from France that anti-terror police had foiled what they claimed was a planned attack on a Christmas market in Strasbourg.
In July, a truck plowed into a Bastille Day crowd in the French city of Nice, killing 86 people. Islamic State claimed responsibility for that attack, which was carried out by a Tunisian living in France.