German police begin search for suspect of Christmas market attack as ISIS claims responsibility

The Islamic State has claimed responsibility for the attack on a Christmas market in Berlin while the German police continue their search for the suspect who drove a truck through the crowd on Monday, killing 12 people and injuring 48.

In a statement published by the Amaq news agency, ISIS said that the attacker "is a soldier of the Islamic State" who "carried out the attack in response to calls for targeting citizens of the Crusader coalition."

The announcement from the terror group came after German prosecutors stated that they just released a man who was initially suspected of driving the truck. The man, who is said to be a Pakistani citizen, was arrested on Monday based on a description of a suspect who fled from the vehicle.

German authorities have named the new suspect as Anis Amri, a 23-year-old Tunisian refugee, after his ID was found under the seat of the truck, according to Mail Online. He came to Germany earlier this year and obtained a temporary permission to stay while his asylum application was still pending.

Security sources warned that Amri has received weapons training abroad and that he is probably armed and "highly dangerous."

The suspect is reportedly a follower of Abu Walla, who is believed to be a leading figure in the Jihadi movement in Germany. Walla was arrested in Hildesheim last month for recruiting radicals on behalf of ISIS. Prosecutors said that his network recruited and provided logistical support for local volunteers who were headed for Syria.

Amri was apparently arrested recently for grievous bodily harm, but he vanished before he could be charged. Authorities believe that the blood that was found in the truck's cab was his, and they assume that he may be badly injured.

Berlin mayor Michael Mueller said that police presence has been increased, and other measures have been taken to find the suspect quickly. However, he noted that there are limits to increasing security, given the number of public spaces and events.

"It wouldn't be our free and open life any more if we escalated security measures so much that people worry about going anywhere, that there are strict entry checks," said the mayor. "We don't want that. It must be appropriate and goal-oriented," he added.