On Monday, a truck rammed into a crowd at the Berlin Christmas market on the Breitscheidplatz square, killing 12 people and injuring over 40 others.
Earlier in the day, German media reported that the fingerprints of Amri and documents presumably belonging to him had been found in the cab of the truck.
German Interior Minister Thomas de Maiziere said on Thursday that additional information has been received proving that Amri is the perpetrator of the attack with a "high probability."
"We can report today that we have new information that the suspect is with high probability really the perpetrator," de Maiziere said.
"In the cab, in the driving cabin, fingerprints were found and there is additional evidence that support this," he added.
Meanwhile, German Chancellor Angela Merkel said that she hopes that the suspect will be arrested soon.