German Federal Criminal Office | Bundeskriminalamt via Getty Images
A man looks on who is purportedly Anis Amri., a 24-year-old Tunisian man, whom authorities suspect of driving a truck that smashed this week into a crowded Christmas market near Kaiser Wilhelm Memorial Church on December 21, 2016 in Berlin, Germany. T
Islamic State has claimed responsibility for the attack, in which the truck mowed through a crowd of people and bulldozed wooden huts selling Christmas gifts and snacks beside a famous church in west Berlin.
One of the 12 dead was the Polish driver from whom the truck had been hijacked. His body, stabbed and shot, was found in the cab.
Police across Europe have been searching for the assailant since the attack on Monday.
Amri was caught on camera by German police on a regular stake-out at a mosque in Berlin’s Moabit district early on Tuesday, Germany’s rbb public broadcaster reported.
Danish police had also said a man matching his description was seen in Aalborg in northern Denmark.
The Berlin attack has put Europe on high alert over the Christmas period.
In the early hours of Friday morning, German special forces arrested two men suspected of planning an attack on a shopping mall in the city of OberhausenIn in the western state of North Rhine-Westphalia.
The men – two brothers from Kosovo, aged 28 and 31 – were arrested in the city of Duisburg on information from security sources, police said.
A police spokesman said there was no connection between the Duisburg arrests and the Amri case.
Amri had been identified by security agencies as a potential threat and had had his application for asylum rejected, but authorities had not managed to deport him because of missing identity documents.