A ‘bomb-like’ device has been destroyed in a controlled explosion in Central Oslo.
Police officers cordoned off a large part of the Gronland area on Saturday evening, before the bomb squad detonated the suspected device.
A police spokesman said a suspect is in custody as police were already on alert after an attack in Sweden on Friday.
A truck ploughed into a Stockholm department store, killing four people and leaving 15 more injured.
It was said to be the worst attack to hit the Nordic region since the 2011 killing of 77 people in Norway by far-right extremist, Anders Brevik.
Swedish police confirmed on Saturday that they had found the unknown device on the driver’s seat in the abandoned lorry, which they were testing.
The investigation has been handed over to Norway’s Police Security Service.