BERLIN (AP) — More than 10,000 people have been evacuated from a residential neighborhood in the German city of Potsdam after the discovery of an unexploded 250 kilogram (550-pound) bomb from World War II in the yard of a house.

It was not immediately clear how long residents would have to stay away from the area after experts were brought in early Friday to defuse the bomb.

Even almost 70 years after the end of the war, there are still estimated to be tens of thousands of unexploded bombs lying underground in Germany.

In August, authorities in Munich were unable to defuse a 250 kg bomb and had to detonate it in place. The explosion blew out the windows of many nearby buildings and caused several fires.

Copyright 2012 The Associated Press.