The explosion threw a mechanical digger onto its side. Photo / AP
Four people were injured when an unexploded World War II bomb went off at a construction site in Munich.
A 550lb bomb dropped by Allied aircraft during the war was detonated by accident during construction work on a new regional railway line in the city.
The explosion threw a mechanical digger onto its side and scattered debris for hundreds of yards. The blast could be heard several miles away, and witnesses described a tall column of smoke over the city.
Four construction workers were injured in the blast, one of them seriously. All train services to Munich central station were suspended.
Unexploded World War II bombs are discovered and defused regularly in Germany, but it is rare for one to go off.
Construction sites are usually checked for any unexploded ordnance before work is allowed to begin.
"We have to find out why this bomb was not detected beforehand," Joachim Hermmann, the Bavarian regional interior minister, said on a visit to the accident site.
Herrmann said the bomb appeared to have been hit during drilling for the new railway line.
The incident took place at the Donnersbergerbrücke bridge, which carries road traffic over the train lines.
British and US aircraft dropped 1.5m tons of munitions on Germany during World War II, and it is believed as much as 15 per cent failed to go off.
Around 2000 tons of unexploded ordnance are still discovered each year, and Germans are used to large areas of cities being evacuated and cordoned off so they can be safely removed.
In 2017, 70,000 people had to be evacuated from their homes in the financial capital Frankfurt after an unexploded 1.4-ton British "Blockbuster" bomb was found.
In 2011, 45,000 people had to leave their homes in Koblenz when a drought exposed another Blockbuster bomb lying undetonated on the bed of the Rhine river.
In 2019 a 550lb bomb that had lain undetected since the war went off in a field outside Limburg in the middle of the night.
The bomb was not disturbed and it is believed it went off because the chemicals in its detonator had decomposed.
No one was injured but the bomb registered 1.7 on the Richter scale and left a 13ft-deep crater.