A Pakistani man arrested in connection with an attack on a Berlin market which left 12 people dead has been released as there is insufficient evidence to hold him, prosecutors said.
The 23-year-old man was arrested in the wake of the attack on Monday night, in which a truck was driven into crowds at a Christmas market in the centre of the German capital.
He denied any involvement in the attack, and in a press conference German police chiefs on Tuesday (20 December) said that he may not be the person responsible, and that the attacker may still be at large.
Holger Münch, the head of the federal criminal police, said: "We need to work on the assumption that an armed perpetrator is still on the loose. As a result of this we are on high alert."
Earlier, a senior Berlin police officer told Die Welt that police had arrested "the wrong man."
The man named as Naved B in German media, had reportedly entered Germany as an asylum seeker in 2015.
Police have urged people to remain "particularly vigilant", and report suspicious activity to a special police hotline. 50 people were also injured in the incident.
German Interior Minister Tomas De Maziere earlier confirmed that the incident was being treated as an intentional attack.
Security has been stepped up at Christmas markets across Germany, and German Chancellor Angela Merkel held a cabinet meeting with security officials on Tuesday to formulate a response to the atrocity.