German police had been repeatedly warned that a Saudi doctor who is suspected of ploughing a car into crowds at a Magdeburg Christmas market posed a terror threat.

The officials said Riyadh warned the German authorities the suspected attacker, Taleb al-Abdulmohsen, a Saudi dissident who described himself as an ex-Muslim, had boasted on social media that “something big will happen in Germany”. It was unclear if police ever acted upon the warnings.

Abdulmohsen, a 50-year-old doctor from Saudi Arabia, had expressed anti-Islam views and described himself as a Saudi dissident, an official said.