On Wednesday, three brothers who are Norwegian citizens of Iraqi origin were arrested. One of them has admitted to planting the bomb at the embassy.
The act is related to the war in the Middle East, the man's lawyer, Øystein Storrvik, confirms.
"You can see that it has to do with the circumstances in the area," he tells NRK.
The explosive device was "very powerful," according to Norwegian police, who are now investigating links to criminal networks.
According to information provided to SVT, Swedish authorities have been informed that the attack may be linked to the Foxtrot network, which has previously been linked to attacks on Israeli embassies. Violent missions are advertised on the encrypted messaging service Signal, SVT reports.
