German police on Friday were investigating a possible explosive device close to a Christmas market in Potsdam, reviving fears of a repeat of last year’s terror attack that struck at the height of the festive season. The device was found in a package at a pharmacy just off the Christmas market in central Potsdam, a picturesque city near Berlin. Police said a pharmacist had sounded the alert after discovering a canister with wires inside the package. Investigators initially said in a tweet that “suspicions of an unconventional explosive device have been confirmed”. But Brandenburg interior minister Karl-Heinz Schroeter later said a probe was still ongoing to determine “whether the device was actually capable of causing an explosion”. Police said the canister was filled with nails and powder, batteries and wires, as well as a powerful firework of a type banned in Germany. But investigators said that there was no sign of a detonator. After clearing parts of the city centre and Christmas market, bomb disposal units defused the device soon before 6pm. Schroeter said officers were combing the area to check if other similar packages had been deposited. It was unclear whether the pharmacy or the market were the target. “Both options are possible,” he said. Christmas market organiser Peter Klemm told broadcaster NTV: “We’re shocked. But the people here understand what’s going on and take the measures very seriously.” Baker Erich Schroeter kept his shop open for people moved during the evacuation. “We wouldn’t just put people out into the cold,” he said. Germany has been on high alert for possible attacks by Muslim extremists after last December’s deadly assault at a Christmas market in central Berlin. The attacker, Tunisian asylum seeker Anis Amri, hijacked a truck, killed its Polish driver then ploughed the heavy vehicle through the market, leaving 11 people dead and dozens wounded. Four days later, while on the run, he was shot dead by police in Milan, Italy. Germany has since been targeted again in attacks with seemingly radical Islamist motives. In July 2017, a 26-year-old Palestinian asylum seeker wielding a knife stormed into a supermarket in the northern port city of Hamburg, killing one person and wounding six others before being detained by passers-by. German prosecutors said the man probably had a “radical Islamist” motive. At the end of October, German police arrested a 19-year-old Syrian identified only as Yamen A. suspected of planning a “serious bomb attack” using powerful explosives. Islamic State claimed responsibility for a number of attacks in 2016, including the murder of a teenager in Hamburg, a suicide bombing in the southern city of Ansbach that wounded 15, and an axe attack on a train in Bavaria that left five injured. Germany remains a target for extremist groups, in particular because of its involvement in the US-led attacks on IS in Iraq and Syria, and its deployment in Afghanistan since 2001. Germany’s security services estimate there are around 10,000 Islamic radicals in Germany, some 1,600 of whom are suspected of being capable of using violence.