Norwegian police stated on Sunday that an explosion at the U.S. Embassy in Oslo overnight may have been an "act of terrorism" linked to the security situation in the Middle East, though they stressed other motives were also being investigated and no suspects had been identified.
An "explosive device" was used in the attack, which struck the entrance to the embassy's consular section at around 1 a.m. local time (0000 GMT) in the Huseby district of western Oslo, police said. The blast caused minor material damage but no injuries.
"One of the hypotheses is that it is an act of terrorism," said Frode Larsen, head of the police's joint unit for investigation and intelligence, in an interview with public broadcaster NRK.
"But we are not completely stuck on that. We have to be open to the possibility that there may be other causes behind what has happened."
Grete Lien Metlid, head of the joint unit for operational services, said the explosive was "thrown" at the embassy but declined to specify the type of device.
"It is an explosive device. Beyond that, we will not comment at this time," she said.
Larsen said it was "natural to see this in connection with the current security policy situation," referring to the war in the Middle East. Police increased security at the scene and reinforced both guard duty and "operational capability" after the attack, with officers now stationed outside the embassy.
Shattered glass was visible in the snow outside the entrance, along with cracks in a thick glass door, overhead lamps dangling from wiring, and black marks on the ground at the foot of the door.
Norway's domestic security service PST said it had called in extra staff to assist police with the investigation.
Spokesman Martin Bernsen said there had been "no change" to the threat assessment level, which has stood at three on a five-point scale, already an elevated "moderate" level, since November 2024.
He refused to disclose whether any threats had been made against U.S. interests in Norway prior to the explosion.
Foreign Minister Espen Barth Eide and Justice and Public Security Minister Astri Aas-Hansen contacted U.S. Embassy charge d'affaires Eric Meyer. Eide said they "expressed that this is an unacceptable act that we take very seriously."
"The security of diplomatic missions is extremely important to us," he said.
Police had no suspects as of Sunday afternoon. Investigators examined the scene overnight while dogs, drones, and helicopters searched for the perpetrators. Several hours after the blast, police declared the area safe.
Metlid said large planned events in Oslo on Sunday, including the International Women's Day march, would proceed as scheduled with no security concerns.
Neighbors described being woken by the explosion. Nine-year-old Matilda Daehlen told NRK: "I just thought, 'what is happening here?' I looked out the window and saw lots of police cars. Suddenly, police with dogs came, and then more and more."
A group of friends waiting for a taxi nearby said they felt three blasts. "We felt three 'bangs' that made the ground shake," Kristian Wendelborg Einung told TV2.
He said the street in front of the embassy was covered in smoke. "The blanket of smoke was very strange. It was like thick fog."