The Daesh Takfiri terrorist group has claimed responsibility for the deadly attack on a Christmas market in Germany.
"One of our soldiers carried out the Berlin operation in response to appeals to target citizens of coalition countries," said the group in a statement published on the Daesh-linked Amaq news agency on Tuesday.
Germany is not directly involved in the US-led coalition anti-Daesh operations but has jets and a refueling plane stationed in Turkey in its support.
The claim was made shortly after German police released a Pakistani asylum-seeker whom they arrested after the attack on the basis that he matched a witness description. According to federal prosecutors, he denied involvement in the incident and there was no forensic evidence to tie him to the attack.
"The accused, detained over the attack on the Berlin Christmas market on December 19, 2016, was let go on this evening on the orders of the federal prosecutor," said a statement.
"The forensic tests carried out so far did not provide evidence of the presence of the accused during the crimes in the cab of the lorry," the statement added.
Following Daesh’s announcement, German Interior Minister Thomas de Maiziere said that investigators are following several leads on the attack.
"We just heard about the supposed claim of responsibility by Daesh group that is in fact a gang of terrorists," de Maiziere told ARD broadcaster.
"There are several leads that investigators are following now," the minister added.
De Maiziere added that "nobody will rest until the perpetrator or the perpetrators are caught."
Meanwhile, Germany's top prosecutor, Peter Frank, told reporters that attack was reminiscent of the attack on the French Riviera city of Nice in July.
"There is also the prominent and symbolic target of a Christmas market, and the modus operandi that mirrors at least past calls by terror organizations," said Frank.
Chancellor Angela Merkel has also stressed that the attack must not change the people of Germany’s way of life.
"Twelve people who were still among us yesterday, who were looking forward to Christmas, who had plans for the holidays, aren't among us anymore," she said in nationally televised statement."A gruesome and ultimately incomprehensible act has robbed them of their lives," she added.
The incident took place late Monday when a truck plowed into a popular Christmas market packed with tourists as well as local shoppers killing 12 people and injuring some 50 more outside the Kaiser Wilhelm Memorial Church near Berlin's Zoo station.