It comes as new developments has been revealed in the search for the suspect, with police conducting raids across several states.
Three days after the deadly truck attack on a Berlin Christmas market, German authorities and their counterparts across Europe continue to hunt for the main suspect.
Across the continent, officials are cooperating with German security and intelligence services in trying to apprehend Tunisian national Anis Amri.
The 24-year-old, alleged to be behind Germany's worst attack in decades, reportedly spent four years in prison in Italy, where his father says he was lured by militant sympathisers.
Tunisian radio is reporting the father has been questioned about his son's links with the self-proclaimed Islamic State.
A spokesman for the office of Germany's federal prosecutor, Frauke Koehler, says more evidence linking the son to the crime has been found in the truck.
"Preliminary results from the investigation show fingerprints on the outside, on the driver's door and on the pillar on the driver's side of the truck. We are confident that Anis Amri controlled the vehicle, and so we've issued an arrest warrant for him today."
Searches have been conducted in the Berlin district of Kreuzberg and in parts of the state of North Rhine-Westphalia, but no arrests have been made.
The tragedy has come at a bad time politically for German chancellor Angela Merkel, with questions raised over her immigration policy ahead of next year's elections.
The admission that German officials had stopped their surveillance of Anis Amri in September over a lack of evidence that he was planning an attack has also intensified scrutiny.
Speaking through a translator, Ms Merkel has defended the government's handling of the situation.
"I can tell you that, over the last years, we've undertaken a great deal of effort in order to be able to face up better to the challenges. We have set up a joint anti-terror network, as one example, and we have also internet surveillance. I am convinced that we will be able to stand the test, because we have professional personnel that are doing everything possible in order to bring the search to a successful conclusion."
Back in Anis Amri's home town in Tunisia, his family is still coming to terms with his alleged involvement in Monday's incident.
His brother Walid has questioned what could have motivated him to do such a thing if he did.
"Whether he did it or not, I ask him to report to the police. We are worried. At least, in the hands of the police, it's more secure than remaining a fugitive. We are worried, as we have no information about his location or status. I want him to hear me. I ask him to turn himself into the police. Then we can find the truth, and we can be in contact with him."
A makeshift memorial of flowers, candles and flags continues to grow at the Berlin Christmas market, now surrounded by concrete barriers.
More than 60 other such markets across the country have tightened security in the wake of the attack.
These shoppers have told Sky News the tragedy was a tipping point for the country and action must be taken.
"It hurts. My heart hurts. It angers me that this is the case. The politicians need to change this, so that it never happens again."
"We're too open in Germany, in my view. It's not that we don't want people to come here, we just need better controls, and that should've been the case for a long time."
