Norwegian police said on Wednesday they apprehended three suspects after Sunday's bombing at the U.S. embassy in Oslo.

Three brothers in their 20s, originally of Iraqi descent and living in Norway for several years, were arrested in connection with the case. Two were taken into custody at their home in Oslo, while a third was arrested in the city as he was on his way home from work, authorities told Newsmax.

The powerful early morning blast from an improvised explosive device (IED) damaged the entrance to the embassy's consular section but caused no injuries, Norwegian authorities have said.

"They are suspected of a terror bombing," Police Attorney Christian Hatlo told reporters.

Images of one of the suspects released by police on Monday showed a hooded person, whose face was not visible, wearing dark clothes and carrying a bag or rucksack.