BERLIN — The German authorities are still looking for the perpetrators of a deadly truck rampage that tore through crowds at a Christmas market early yesterday, almost a day after the attack which killed 12 people and injured scores of others.

While the authorities are treating the incident as an act of terrorism, they are struggling to piece together the full picture of the deadly attack — after having initially caught a suspect they said was an asylum seeker, only to voice doubts minutes later over his involvement.

Interior Minister Thomas de Maiziere said the arrested 23-year-old man, who denied involvement, was from Pakistan and was in the process of applying for asylum. A security source said he was known to the police for committing minor offences and had been staying at a refugee centre in the now-defunct Tempelhof airport.

But minutes after Mr de Maiziere’s announcement, Berlin police president Klaus Kandt said it was unclear if they had the right man. “As far as I know, it is indeed uncertain if he was the driver (of the truck),” Mr Kandt told a press conference.

“The initial evidence has been limited”, he said, while the police tweeted that “we remain especially vigilant”, urging Berliners to do the same.

German Die Welt newspaper also quoted security sources as saying the arrested man was not believed to be the perpetrator.

“We have the wrong man,” a police chief told the paper. “And therefore a new situation. The true perpetrator is still armed, at large and can cause fresh damage.”

In the attack, a tractor-trailer truck jumped a sidewalk early yesterday and ploughed into a Christmas market near the Kaiser Wilhelm Memorial Church, a symbolic Berlin site whose spire, jagged from bomb damage, was intentionally left unrepaired after World War II.

The vehicle smashed into wooden huts serving mulled wine and sausages at the foot of the church. Besides the 12 killed, 48 people were injured — 18 severely. The driver fled after the attack. The police later said they arrested a man near the scene who was suspected of involvement.

German Chancellor Angela Merkel said yesterday she was “shocked, shaken and deeply saddened” by the deadly rampage, which was believed to be a “terrorist attack”.

She said that if it was confirmed that the killer had been part of the refugee influx, this would be “particularly sickening in relation to the many, many Germans who are involved every day in helping refugees”.

Yesterday’s incident evoked memories of an attack in Nice, France, in July, when a Tunisian-born man drove a 19-tonne truck along the beachfront, mowing down people who had gathered to watch the fireworks on Bastille Day, killing 86 people. That was claimed by Islamic State (IS).

It came less than a month after the United States State Department warned that extremist groups including IS and Al Qaeda were focusing “on the upcoming holiday season and associated events” in Europe, following calls by the two terror groups to their followers to use trucks in particular to attack crowds.

The US condemned an apparent “terrorist attack”, while President-elect Donald Trump blamed “Islamist terrorists” for a “slaughter” of Christians.

The Christmas market attack fuelled immediate demands for a change to Ms Merkel’s immigration policies, under which more than a million people fleeing conflict and poverty in the Middle East, Africa and elsewhere have arrived in Germany this year and last.

The record influx has hit Ms Merkel’s ratings as she prepares to run for a fourth term next year, and boosted support for the anti-immigrant Alternative for Germany (AfD). AfD leader Frauke Petry said Germany was no longer safe, claiming that “radical Islamic terrorism has struck in the heart of Germany”.

The general mood in Berlin was subdued yesterday after the attack. People went about their business calmly but much more quietly than usual. “People are a little bit taking time off, and a little bit afraid,” said Mr Memo El-Schafie, 47, a vendor at a coffee and cake stand in the Stadtmitte subway station, where there were notably few passengers for a weekday morning.

The site of the incident remained cordoned off as investigators removed the black truck for a forensic examination. People left flowers, candles and notes at the scene, one of which read: “Keep on living, Berliners!”

Berlin police are investigating leads that the truck had been stolen from a construction site in Poland, amid signs that it could have been hijacked.

The authorities said a Polish man was found shot dead inside the vehicle, but the Interior Minister said no gun had yet been found. Officials indicated that they considered the Polish man a victim and not a perpetrator. AGENCIES