The Islamic State extremist group is claiming responsibility for the truck attack on a Berlin Christmas market that killed 12 people and left nearly 50 injured.

The Islamic State group's Amaq news agency said in a statement Tuesday that "the person who carried out the truck run over attack in Berlin is a soldier of the Islamic State and carried out the attack in response to calls for targeting citizens of the Crusader coalition."

German police are still hunting for the driver of the truck, which slammed into the downtown Christmas market Monday night. A Pakistani citizen taken into custody on the day of the attack was released because prosecutors say that there wasn't sufficient evidence to tie him to the rampage.

Prosecutors noted that witnesses were able to follow the truck's driver from the scene but lost track of him. The man arrested matched witness descriptions of the truck driver, but investigators haven't been able to prove that he was in the truck's cab at the time of the attack.

Germany is not involved in anti-IS combat operations. But it does have Tornado jets and a refueling plane stationed in Turkey in support of the coalition fighting militants in Syria, as well as a frigate protecting a French aircraft carrier in the Mediterranean.