The disposal of an unexploded World War II bomb brought disruption to Berlin Friday as police began attempts to defuse a 500-kilogram (1,100-pound) explosive.
The 500kg British bomb was discovered during building work this week.
The zone includes government ministries, a hospital and the city's central railway station.
The operation will affect long-distance and commuter rail services passing through Berlin's main station from 9 a.m. (0700 GMT) onward.
It is the latest in a number of unexploded bombs found recently in Germany including one at Berlin's Tegel airport and another in Frankfurt past year, which led to the evacuation of 65,00 people.
Local bus and train routes have been disrupted during the operation while roads surrounding the station have been closed.
Police said the 500kg (1,100lb) bomb, believed to have been made in the United Kingdom, posed no immediate danger but the operation was expected to cause transport chaos in the German capital.
The bomb was defused by a team of five police specialists, and it was transported to an area outside of town before being destroyed in a controlled explosion.
They said the bomb was "safe for now", reassuring nearby residents that "there is no immediate danger".
Away from the evacuation site, Berlin's Tegel Airport said Friday's schedule will run as normal.
An estimated more than 2,000 tons of bombs and ammunition are unearthed in Germany each year.
A dismantled World War Two bomb is transported at a construction site next to the central train station in Berlin, Germany, April 20, 2018.
In September, a 1,400-kilogram bomb discovered in Frankfurt led to almost 60,000 people being evacuated while experts defused the device.