A large police and rescue operation was dispatched to Kampen in eastern Oslo on Wednesday afternoon after an alarm about an explosion and smoke development.
The bang was heard in a residential area in the Norwegian capital. Both police cars, fire trucks, ambulances, as well as a helicopter and drone were sent there.
There is no information about personal injuries or damage to buildings.
Everything indicates that this (the explosion) occurred at ground level, says police operations leader Thomas Brodal to NRK.
At 22.15, the police announced that a young man in his late teens had been arrested.
He is suspected of illegal possession of explosives, says Andreas Jansen at the Oslo police to Aftenposten.
