Berlin - German authorities have launched a Europe-wide manhunt for a Tunisian man with ties to Islamic extremists who has been identified as a suspect in the Berlin Christmas market attack, lawmakers said on Wednesday.The man is being sought in Germany and across Europe's border-free travel zone, Interior Minister Thomas de Maiziere said after briefing Parliament's domestic affairs committee. He stressed "this is a suspect, not necessarily the perpetrator. We are still investigating in all directions."Twelve people were killed and 48 others injured when a truck ploughed into a popular Berlin market on Monday evening. The Islamic State group has claimed responsibility.De Maiziere wouldn't give details on the new suspect, but committee members said he's believed to be Tunisian.The man is in his early 20s and apparently has used various identities, said Stephan Mayer, a senior lawmaker with Germany's governing conservatives. He said the man was considered part of the "Salafist-Islamist scene" by authorities and apparently had previously spent time in pre-deportation detention in Germany after his asylum application was rejected.Germany's chief federal prosecutor told lawmakers that "this Tunisian is a solid lead, his wallet was found in the cab of the truck, but that it's not clear that he was also the perpetrator," said Burkhard Lischka of the Social Democrats, the junior governing party.Nice attack A Tunisian official said German investigators are trying to determine the role of the man, who he said was named Anis Amri. The official, speaking on condition of anonymity because the German government hasn't publicly commented on the potential suspect, said Tunisian authorities are requesting more information on the German probe into the suspect. He declined to comment further.A Tunisian living in France was shot to death after carrying out a similar attack on July 14 Bastille Day revellers in the southern French city of Nice, killing 86 people.Frank Tempel, a lawmaker with Germany's opposition Left Party who attended Wednesday's briefing, said "the hypothesis that the trail in the truck was a false trail can't be dismissed out of hand."Shortly after the Monday evening attack, police arrested a Pakistani man found about a kilometre from the market who matched witness descriptions of the truck's driver. However, they released him the next day, saying they did not have evidence tying him to the attack.Police in Berlin said they had received over 500 tips on the attack.ISIS The claim of responsibility carried on the ISIS group's Amaq news agency did not identify the man seen fleeing from the truck, but described him as "a soldier of the Islamic State" who "carried out the attack in response to calls for targeting citizens of the Crusader coalition".Germany's top prosecutor, Peter Frank, told reporters before the claim that the attack was reminiscent of the Nice rampage and appeared to follow instructions published by ISIS."We don't know for sure whether it was one or several perpetrators," he said. "We don't know for sure whether he, or they, had support."Christmas shoppers were out again in the streets on Wednesday in the German capital, and Berlin Mayor Michael Müller said it was "good to see that Berliners aren't being intimidated"."I don't think there's any need to be afraid," he told ZDF television. "The police presence has been significantly heightened ... and of course other measures taken to find the perpetrator quickly."Müller argued that there are limits to increasing security, given the number of public spaces and events."It wouldn't be our free and open life any more if we escalated security measures so much that people worry about going anywhere, that there are strict entry checks," he said. "We don't want that. It must be appropriate and goal-oriented."