The western German city of Duesseldorf has closed off its old town area, where its Christmas market is located, a spokesperson for the city said on Monday.
The city spokesperson did not comment on what prompted the closure.
The Bild newspaper, citing police, reported that the Christmas market in the old town area as well as others across the city were closed after a threat was reported.
Police evacuated the Christmas markets as a precaution after acaller had threatened to crash a truck into the market at the city town hall, Bild reported.
Just over a week ago, police in Berlin closed roads and stepped up security around the Alexanderplatz Christmas market due to a phoned-in threat.
Berliner Zeitung reported at the time that an unidentified person had called police saying he planned to plough his car into the crowds of revellers.
Police gave the all-clear after about three hours, saying it was investigating suspected abuse of the emergency hotline.
Twelve people were killed in 2016 after a man drove a stolen truck into a busy Christmas market in Berlin.