German police are hunting a Tunisian man over the Berlin market attack after finding an identity document in the lorry, according to reports.
The document was found under the driver's seat of the vehicle that ploughed into crowds at the Christmas market on Monday evening, killing 12 people.
Der Spiegel and Allgemeine Zeitung reported that the document, apparently asylum office papers announcing a stay of deportation, was in the name of Anis A, born in 1992 in Tataouine, Tunisia.
The suspect was also known to have two aliases, according to the newspapers.
Bild said Anis A was known to police for bodily harm and is considered dangerous.
German media has said a police operation is under way in the North Rhine-Westphalia state as the manhunt continues.
A migrant shelter in Emmerich, near the border with the Netherlands, is also being searched, according to the Rheinische Post.
Die Welt said the identity documents were issued in Kleve, and the suspect - who had applied for asylum - had an address in Berlin and North Rhine-Westphalia.
He had been charged with assault in the summer, but failed to appear in court, the newspaper reported.
Newspaper Sueddeutsche Zeitung said the suspect had been in contact with the network of a leading Islamist ideologist known as Abu Walaa.
COMMENT: If the Obamans were running the search, they'd call it a case of road rage. Nothing to see, nothing to see.
The attack follows a pattern in which ordinary vehicles are used, rather than weapons or bombs. Such attacks are easy to mount and almost impossible to stop.