The discovery of an unexploded World War II bomb near Berlin's main railway station has disrupted the morning commute for thousands of workers, BBC News reported.
Roads have been closed and there are long delays on main railway lines.
Specialists have been called in to decide whether to remove or disarm the 100kg (220-pound) device.
There are thought to be thousands of unexploded bombs buried in Germany. In 2010, three people were killed when one unexpectedly detonated.
A police spokesman said the area surrounding the Berlin bomb, which was found in Heidestrasse, would be cordoned off. He said the authorities would decide what to do with the bomb at about 09:00 local time (07:00 GMT).
