Police in the western German city of Essen have ordered a shopping center in the center of town to remain closed on Saturday due to "concrete indications about a possible attack".
"The current state of our investigations points to the threat being exclusively at the shopping center," said the police in a statement, adding it could give no further details about the nature of the threat.
Germany is on high alert following major radical attacks in France and Belgium and after a failed asylum seeker from Tunisia drove a truck into a Christmas market in December, killing 12 people, Reuters reported.