Twelve people were killed and at least 48 injured when a truck ploughed into a crowded Christmas market in Berlin on Monday.
The truck crashed into the holiday market and continued for about 60 meters before coming to a stop.
Earlier police had said they were following a number of good leads.
A man suspected to be the driver was detained two kilometers from the scene.
A suspect arrested after the attack “comes from Pakistan” and had applied for asylum, Interior Minister Thomas de Maiziere said Tuesday.
He entered Germany as a migrant on December 31 past year and arrived in Berlin in February. The police has not confirmed the man’s nationality. But they found no evidence of a plot and closed the investigation in September.
Photographs from the scene showed the black lorry askew across a road, surrounded by debris from smashed Christmas market huts and stalls.
“We have further increased our presence at Christmas markets and on Strøget after Berlin“. The driver fled on foot, but was arrested nearby police said. Police have since checked statements by the man and found it credible that he was not involved, Die Welt reported, citing people close to the authorities. They urged people to watch out for and report suspicious movements or behavior.
German police are searching for a Tunisian man in connection with the truck attack which killed 12 people at a Berlin Christmas market on Monday, according to media reports.
The accused who had been temporarily arrested on the occasion of the attack on the Berlin Christmas market on 19 December 2016 was released in the evening on the orders of the Federal Prosecutor.
German authorities were still investigating the event but The White House says it “appears to have been a terrorist attack”.
But officials at North Rhine-Westphalia police did not deny the operation and The Independent understands more details may be released later.
Chancellor Angela Merkel has expressed shock and deep sorrow on Tuesday for the deadly attack, but also vowed that Germany will not bow to terrorism. Following this report, the USA -based SITE Intelligence Group, which monitors the online activity of militant groups, said no one has claimed responsibility for the attack so far. The Islamic State also claimed responsibility for that massacre.