German authorities say the truck attack in a crowded Berlin Christmas market was an "act of terrorism" that followed instructions published by ISIS.
A black tractor-trailer rig crashed into a shopping area near the landmark Kaiser Wilhelm memorial church Monday night, killing 12 people and injuring 48 others. The place of worship is a famous tourist spot in western Berlin because it still bears bombing scars from World War II.
A man who was taken into custody following the attack was released Tuesday due to insufficient evidence. The driver is still at large.
German's top prosecutor, Peter Frank, told reporters Tuesday that the attack was modeled after a terror strike in Nice, France, in which a truck driver killed 84 revelers on Bastille Day.
In online posts, ISIS has provided a guidebook on the efficacy of using trucks as weapons. "There is also the prominent and symbolic target of a Christmas market, and the modus operandi that mirrors at least past calls by jihadi terror organizations," he said.
There have been no claims of responsibility, he said.
Chancellor Angela Merkel made an emotional appeal on national television Tuesday for citizens to carry on in the holiday spirit and to remember the victims.
"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. "A gruesome and ultimately incomprehensible act has robbed them of their lives."
She also addressed the possibility that an asylum seeker may have carried out the attack. The chancellor has faced political criticism for allowing thousands of migrants fleeing Syria to enter Germany.
"I know that it would be particularly hard for us all to bear if it were confirmed that a person who committed this act asked for protection and asylum in Germany," she said.
Police urged Berliners to be "particularly vigilant" and to report "suspicious movement" to a newly established hotline.
Australian Trisha O'Neill said the truck's driver "didn't want to stop, he just kept on driving," she told the Australian Broadcasting Corp. "I just saw this huge black truck speeding through the markets crushing so many people and then all the lights went out and everything was destroyed," she said.
The Christmas market is one of several hugely popular holiday offerings of mulled wines, winter foods, yule trinkets and ornaments.
British tourist Mike Fox told The Associated Press that the massive truck missed him by about three yards.
"It was definitely deliberate," Fox said. He said he helped people who appeared to have broken limbs, and that others were trapped under Christmas stands.
Late Monday, videos taken by survivors of the chaotic scene began appearing on YouTube.
A passenger in the truck was shot to death. The truck is believed to have been hijacked somewhere along its route from Poland to Berlin. The vehicle carried Polish license plates, according to reports.
The truck's owner, Ariel Zurawski, told Polish news channel TVN24 that his cousin had been driving the vehicle and hadn't been heard from for hours.
The U.S. condemned the incident.