German police sealed off and closed a shopping mall in the heart of the western city of Essen on Saturday after the security services warned of a possible terrorist attack.
Months on, terror police in Germany said they have indications of another attack, without providing further details.
Authorities ordered the shopping mall and adjacent auto park to stay closed all day as about 100 armed police officers evacuated the area and stood guard to prevent anyone from entering.
Earlier, a police spokesman told a German broadcaster they believed the Limbecker Platz shopping center was under threat of a possible terrorist attack.
Two men in the nearby town of Oberhausen were arrested in connection with the threat.
The spokesman added: "In order to avoid possible danger to visitors, they will not be able to enter the shopping halls or the vehicle park".
Germany remains on edge after a pair of deadly incidents previous year.
And Germany is already on high alert following the Berlin Christmas market attack in December, which killed 12 people.
Hundreds of police are involved in the security operation at the Limbecker Platz mall, which was locked down before it opened to the public, Essen police spokesperson Christoph Wickhorst said. The suspect, a Tunisian man, was shot dead by police days after the attack, which ISIS claimed it inspired.