German Interior Minister Thomas de Maiziere said the suspect is from Pakistan and entered Germany on Dec. 31, arriving in Berlin in February. He also said the man applied for asylum in Germany.
German Chancellor Angela Merkel said Tuesday authorities are assuming the incident was a terrorist attack.
The truck plowed into the market outside the landmark Kaiser Wilhelm Memorial Church Monday evening as Germans celebrated the Christmas season with traditional outdoor festivities.
The suspected driver was arrested about two kilometers away, while a second person found inside the truck died at the scene while undergoing medical treatment.
Merkel said it would be “especially hard for us all to bear” if someone who sought protection and asylum was responsible.
“This would be especially despicable for the many, many Germans who day in, day out are active working for refugees as well as for those people who actually need our protection and who make an effort to integrate into our country,” she told reporters.
Witnesses said the popular Christmas market was packed with tourists and locals when the truck, believed traveling in excess of 60 kilometers an hour, slammed into it. Authorities said the vehicle was loaded with steel beams.
The U.S. State Department had earlier called for caution in market places and other public sites across Europe. A published U.S. travel alert said extremist groups were focusing their attention “on the upcoming holiday season and associated events.” It also warned U.S. citizens on the continent to be on the alert for “self-radicalized” extremists, who it said could strike without warning.
The Polish owner of the truck, which had Polish license plates, said he feared the vehicle, driven by a relative, may have been hijacked.
Ariel Zurawski said he last spoke with his cousin several hours before the crash, and was told that the truck was set to be unloaded Tuesday.