BERLIN (AP) — A train station, an opera house, a TV station and several apartments were to be evacuated in the western German city of Cologne on Tuesday as as experts prepared to defuse an unexploded American bomb from World War II.

The 500-kilogram (1,100-pound) bomb was found Monday evening during construction works near the Rhine river in the center of the city. Shipping on the river and air traffic was also to be interrupted before the operation gets underway around noontime, the German news agency dpa reported.

Officials also plan to close down a bridge across the Rhine river that takes most trains to Cologne's main train station, one of the major rail hubs in Germany. The suspension of traffic in Cologne will likely lead to delays in train services across all of Germany, officials said.

Almost 75 years after the end of the war, unexploded bombs are frequently found in Germany. Disposing of them sometimes entails large-scale evacuations as a precaution.