Updated 8.40pm
Islamic State have claimed responsibility for yesterday's Berlin attack in which 12 people were killed when a truck ploughed into crowds in a Christmas market.
"The executor of the operation.. in Berlin is a soldier of the Islamic state and he executed the operation in response to calls to target nationals of the coalition countries," the militant group's AMAQ news agency said.
The announcement came shortly after German police released a man who was arrested shortly after the attack on suspicion that he was the driver of the truck.
The Pakistani asylum seeker was arrested in the aftermath of yesterday's attack but denied any involvement.
Police admitted the person behind the attack may still be armed and at large.
The Pakistani man was released because there was not enough evidence to link him to the attack.
It came after federal public prosecutor Peter Frank said the "modus operandi" of the attack had echoes of July's atrocity in Nice, in which 86 people died, and could have been the work of Islamic extremist groups, with the target of the attack "highly symbolic".
But he told a press conference it was unclear if the attacker had an Islamist background, adding: "For now we don't know whether there was one attacker or several attackers. We also don't know whether they had support...
"We have to think that the person who was arrested yesterday, a man of Pakistani nationality, we have to be open to the idea that he could possibly not have been the attacker."
German chancellor Angela Merkel and senior officials visited the scene of the attack, laying white roses among candles at a makeshift shrine to the dead and injured.
Earlier Mrs Merkel said: "Millions of people, including myself, are asking ourselves, how can you live with the fact that, while celebrating the festive season where we want to celebrate life, somebody has come along and took so many lives? I only know that we do not want, and we cannot live with it.
"We do not allow ourselves to be paralysed by terror. Although this might be difficult in these hours, but we will find a strength to continue living life as we want to live it in Germany, in freedom and openness and together."