A mother and her three sons have been remanded in police custody for up to four weeks, following a Norwegian court’s ruling on Friday. They are suspected of participating in the bombing of the U.S. embassy in Oslo last week.

The embassy sustained damage from the powerful early-morning blast on Sunday, which was caused by an improvised explosive device (IED) that disrupted the consular section’s entrance, although, fortunately, no injuries were reported, authorities confirmed.

While one of the suspects has admitted to placing the device, the remaining three have denied any involvement, according to statements from their lawyers.

(With inputs from agencies.)