Berlin attack: ISIS claims it inspired deadly truck assault at market

After releasing a suspect, the German authorities have intensified their manhunt for the culprit who plowed a tractor-trailer truck into a crowd at a Berlin Christmas market leaving 12 dead and 48 injured, even as ISIS claimed that it inspired the attack.

CNN reports that the police said they didn't have enough evidence to hold the Pakistani national they'd earlier described as a suspect in the Monday night truck assault.

General prosecutor at Germany's Federal Court of Justice Peter Frank told the media that there may be more than one suspect at large who could be armed and dangerous.

The ISIS-affiliated Amaq news agency released a statement saying Monday night's attack was carried out by "a soldier of the Islamic State" in response to calls by the group's leadership to target citizens of international coalition countries.

German authorities are investigating the attack as an act of terror. Chancellor Angela Merkel told journalists that we must "assume this is a terrorist attack."

"The results of the investigation thus far have not produced imminent suspicion against the accused," the general prosecutor said in a statement.

Investigators had initially described the asylum seeker they detained as a suspect. But a day later, they seemed to be backing off that claim.

"We possibly need to assume that we have not arrested the right one. We do not know if there was one perpetrator or several perpetrators yet. We do not know if there was support given to the perpetrator," Frank said.

Meanwhile, the Berlin police has turned to the public for help and tweeted that they'd received 508 leads, also asking citizens to upload any digital video and photos of the incident or possible suspects.