German state prosecutors have arrested a 40-year-old Tunisian man in connection with last week’s attack on Berlin’s Breitscheidplatz Christmas market.

According to prosecutors, the man’s number was found on the phone of Anis Amri, who killed 12 people by hijacking a truck and ramming it through the stalls.

German police raided the home and workplace of the man in the Tempelhof area of Berlin, German media report.

Officials have until December 29 to decide whether to formally arrest him.

Anis Amri was shot dead by police in Milan on December 23, four days on from the attack, after the 24-year-old Tunisian opened fire and injured an officer during a routine check.

Meanwhile, police in the Netherlands say it was highly likely Anis Amri was spotted on CCTV in Nijmegen station.

They are investigating whether he traveled there immediately after the market attack, following the discovery of an unused Dutch Sim card in his backpack.

Police believe Anis Amri was probably handed the Sim card in Nijmegen station.

From Nijmegen, it is thought Anis Amri took a six-hour bus trip to Lyon Party-Dieu station in France – from where he apparently got a train to Milan via Chambery and Turin.

The Sim card found in his backpack was issued between December 20 and 22 in one of three possible Dutch cities – Breda, Zwolle and Nijmegen, Italian media reported.

It was widely reported after the attack that German police had searched a refugee center in Emmerich, just across the border at Nijmegen.

That Anis Amri was able to travel from Berlin while subject to a European arrest warrant has raised security questions.