“Large resources” were dispatched to the area in the Norwegian capital at around 01:00 local time (00:00 GMT), Norwegian Police said, as quoted by BBC.

“The police are in dialogue with the embassy and no injuries have been reported,” authorities said in a statement.

Officials have not yet determined what caused the explosion or who might be responsible.

Eyewitnesses told media outlets that a loud blast was heard near the embassy compound in western Oslo at around 1 a.m.

A local resident, Anna Gilbo, told CNN she was at home with friends when she heard the explosion and rushed to the window, where she saw “a cloud of smoke” rising from the building.

“I was watching TV and heard a loud bang while the whole house shook. There was a search going on for a while after the explosion which worried my friends and me, but it feels like the threat is over,” she said.

The incident comes amid escalating tensions in the Middle East following the February 28 US–Israel strikes on Iran, when the United States and Israel reportedly targeted sites in Iran.

In retaliation, Iran allegedly targeted multiple United States diplomatic missions across several Gulf countries.

Authorities in Norway have launched an investigation, and the search for those responsible for the explosion is ongoing.