BERLIN — A Russian bomb dropped on Berlin during World War II was defused by explosives experts, allowing transport to resume Wednesday and people in the affected area of the German capital to return to their homes.

Police earlier sealed off a zone of downtown Berlin immediately to the north of the main railway station before bomb disposal specialists could begin deactivating the device.

It took about 30 minutes to remove the detonator from the 100- kilogram (220-pound) bomb, which was packed with 50 kilograms of explosive, police spokesman Jens Berger said by telephone today.

Bomb specialists dug up the device Tuesday along the main north-south axis leading from the railway station. All rail, road and waterway traffic was halted in the vicinity Wednesday, N24 television reported.

Regional rail services were disrupted and some intercity trains were rerouted to avoid the northern line, Achim Stauss, a spokesman for Deutsche Bahn AG, the state-owned rail operator, told reporters.

The bomb was located by the railway line between Lehrter Strasse and Heidestrasse, less than a kilometer (3,200 feet) from the chancellery across the River Spree. Chancellor Angela Merkel is currently on vacation in Italy.

The bomb squad, police, Berlin authorities and Deutsche Bahn representatives were all involved in the decision to defuse the device rather than attempt to move it. Earlier, police went from house to house evacuating residents in the neighborhood of Lehrter Strasse, Perleberger Strasse and Kruppstrasse.

Allied bombs are routinely unearthed on German construction sites almost 70 years after the end of the war. Berlin city authorities have a department dedicated to WWII bomb disposal.

Three explosives experts were killed and six injured while attempting to defuse a 500-kilogram bomb in the central city of Goettingen in June 2010, one week after an American bomb armed with a similar charge was found by construction workers in the upmarket Berlin district of Zehlendorf.