"Explosives were found at the farm," police prosecutor Trine Dyngeland told Reuters. "The police carried out a controlled detonation of the explosives."
She said no one was hurt in the controlled blast, at Rena, about 160 kms (100 miles) north of Oslo
. She declined to estimate what quantities were found.
Police believe that Breivik made his bomb using fertilizer as a main ingredient. He bought fertilizer under the cover that he was a farmer.