German police in the city of Essen shut down one of the country’s biggest shopping malls on Saturday after security services warned it might be the scene of a terrorist attack. “Yesterday, we received very serious indications from security sources that a possible attack was planned here for today and would be carried out,” a spokesman for the city’s police department told Reuters. “That is why we were forced to take these measures,” the spokesman said. Armed police and security vehicles could be seen throughout the day patrolling outside the Limbecker Platz mall, but police provided no further details on the possible attack. The country has been on high alert after an attack on a Christmas market in Berlin in December killed 12 people.