Four were injured in an explosion of a World War II-era bomb in Munich, Germany, on Wednesday.

Bavaria's state interior minister, Joachim Herrmann, said the bomb was found at a construction site, according to a German news agency, The Associated Press reported.

The construction was taking place near a railway line by Donnersbergerbruecke Station. No tracks were damaged, and trains were able to resume a few hours later. 


One of the four people was seriously injured from the explosion, and trains were temporarily suspended from the station. 

Herrmann said there will be an investigation into the reason the bomb wasn’t discovered sooner. Normally, a construction site is swept for bombs before work begins. 

Finding bombs from World War II, especially at construction sites, in Germany still occurs frequently, the AP noted.