Explosion at US embassy in Oslo may have been deliberate attack

No injuries were reported at the U.S. embassy in Oslo, Norway after what the city's police called a deliberate attack on the building.

Oslo police officials suggested at a news conference that the loud explosion, heard early on the morning of March 8, could be connected to the ongoing U.S.-Israeli war on Iran. 

"It's natural to see this in the context of the current security situation and that this could be an attack deliberately targeting the U.S. embassy," Frode Larsen, head of the Oslo police investigation, said during a press briefing.

No suspects have been identified, but Larsen said that police are searching for one or several perpetrators.

"One of our hypotheses is that this is terrorism, but we are also exploring other options," Larsen told public broadcaster NRK.

While embassies usually have strong security protocols, it is unclear exactly what protection the Oslo embassy had at the time of the explosion. Larsen said police are cooperating closely with the embassy.

The blast occurred at 1 a.m. local time, sending thick smoke into the street by the entrance of the consular section, eyewitnesses said. Police said no further explosive devices had been found in the area.

Kristian Wendelborg Einung, a woman who was waiting for a taxi with friends near the explosion, told Norwegian television station TV2 that there were "three 'bangs' that made the ground shake."

"There was a very thick layer of smoke on the street," Sebastian Toerstad, a high school student who drove past the embassy at the time of the explosion, said.

A State Department spokesperson said in an email to USA TODAY that the department was investigating the bombing and thanked Norwegian authorities for supporting its investigation, but had no further comment. The department has previously warned all Americans to exercise increased caution while traveling abroad in the wake of the continuing war.

USA TODAY has also reached out to the embassy for comment, which referred back to the State Department.

Norway's government was in contact with officials at the U.S. embassy to convey that this was "an unacceptable act that we take very seriously," Foreign Minister Espen Barth Eide said in a statement.

"The security of diplomatic missions is very important to us," he said.

This story has been updated with new information

Contributing: Reuters