Three people were killed when an airport hangar collapsed in Boise, Idaho, officials have confirmed.

Nine other people were injured when the building collapsed in the grounds of the city’s airport at around 5pm on Wednesday. City officials said five of the injured were in critical condition.

Boise Fire Department operations chief Aaron Hummel said they had accounted for everyone who had been at the site when the steel-framed hangar collapse.

“It was a very chaotic scene,” he said, describing the incident as “catastrophic” and a “large-scale collapse” of the framework of the building.

“I don’t know what caused it, but I can tell you it was a pretty global collapse.”

He said some of the victims were on a hoist or other elevated platform at the time the structure fell and confirmed a crane also collapsed in the incident.

Boise Airport operations were not impacted, officials said.

Authorities are investigating what caused the collapse which happened next to Jackson Jet Centre, which offers private airplane charters and maintenance, and city permitting records show permits to build a jet hangar for the company.

Jackson Jet Centre chief executive Jessica Flynn said in a statement their “hearts go out to everyone affected by this horrific event”.

“We do not know exactly what caused the hangar collapse,” she said. “Our focus now is on supporting our team and partners during this difficult time.”