The suspect detained over the Berlin Christmas market incident in which at least 12 people died and 48 were injured has been named as a Pakistani refugee Naved B.
Police believe the man, named as "Naved B", arrived in Germany around one year ago, according to local media reports.
Special forces stormed the makeshift migrant camp at the Flughfen Tempelhof airport hangar where he was believed to live.
The German authorities have so far not described the incident as a terror attack, but speaking to reporters on Monday night, Minister of the Interior Thomas de Maiziere said there are many things "pointing towards one".
And security services have said they are treating the tragedy as deliberately intended to cause harm.
The Berlin market suspect was arrested around one mile (1.6km) away after allegedly fleeing the scene on foot.
He is not known to have any previous link to terror but has a history of petty crime, a German daily newspaper said.
The lorry, a large black Scania, smashed into crowds gathered around brightly lit market stalls surrounding the city’s landmark Kaiser Wilhelm memorial church close to Berlin’s Kurfurstendamm boulevard shortly after 8pm local time (9pm GMT) on Monday.
Eyewitnesses said injured victims lay bloodstained on the ground while others fled the scene in panic after the lorry struck, driving at a speed of some 40mph. More victims were buried under collapsed wooden market stalls.
“A lunatic has driven into the Christmas market. People are screaming. It’s carnage,” one distressed marketgoer told Germany’s Bild newspaper. It was the city’s worst 'attack' in more than a decade.
Police said one of the two drivers was found dead inside the vehicle’s cabin and was thought to have died of injuries sustained in the incident.
A police spokesman said the suspected co-driver’s identity was being checked. He said the Scania lorry had Polish number plates and that the lorry had been stolen. “This appears to have been a deliberate attack,” he said.
German television footage showed the entire Christmas market area sealed off by police as ambulance crews ferried bloodstained victims to hospital in the surrounding area.
Eyewitnesss Mike Fox from Birmingham, told the Associated Press that the lorry missed him by about three metres as it drove into the market, tearing through tables and market stalls.
“It was definitely deliberate,” he said, adding that he had helped people who appeared to have broken limbs and others trapped under Christmas stands.
The incident occurred at the Breitscheidplatz Christmas market, a focal point in west Berlin which stands next to the preserved remains of the city’s Second World War-bomb damaged Kaiser Wilhelm church. The site is a famous tourist attraction.
Chancellor Angela Merkel has been in contact with the interior minister and the mayor of Berlin. Her spokesman, Steffen Seibert, tweeted: "We are in mourning for the dead and hope that the many injured can get help."
Mr De Maiziere told ARD television: "I don't want to use the word 'attack' yet at the moment, although a lot speaks for it."
He added that "there is a psychological effect in the whole country of the choice of words here, and we want to be very, very cautious and operate close to the actual investigation results, not with speculation."
Wolfgang Bosbach, an MP from Chancellor Angela Merkel’s ruling Christian Democratic party, said: “Although there is a host of unanswered questions, indications are it was a deliberate attack... just a few days before Christmas, in the middle of the German capital and amidst happy, peaceful people. The message is clear: no matter where, no matter how, we can pounce at any time.”
Berlin’s mayor, Michael Müller, said: “What we’re seeing here is dramatic and a shock to us all. We hope what our fears that this is an attack won’t prove true. Our thoughts are with the families of the injured.”
US President-elect Donald Trump condemned the suspected attack, saying in a statement: "Isis and other Islamist terrorists continually slaughter Christians in their communities and places of worship as part of their global jihad."
Unlike France, Britain and Spain, Germany has managed to escape a major terrorist attack during the past decade. But the country’s security services warn that the likelihood of an attack is ever present and have asked the public to remain vigilant.
Monday’s incident has echoes of last July’s terrorist attack in Nice, France, that left 86 people dead. A Tunisian-born man drove a 19-tonne truck along the beach front, striking down people who had gathered to watch the fireworks on Bastille Day. The attack was claimed by Isis.
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