The fire that brought first responders to Canfield Mountain was deliberately set, according to officials from Idaho’s Northern Lakes Fire District, NBC reported.

Firefighters were met with gunfire shortly after arriving at the scene, and authorities say the word “ambush” accurately describes what happened to those first on site.

A federal official, speaking on condition of anonymity to the outlet, confirmed early indications that the attack was carried out in ambush style.

A SWAT team has found the body of a man on Canfield Mountain, along with a firearm nearby, according to Kootenai County Emergency Management.

The “shelter in place” order was lifted, although authorities warn the wildfire in the area remains active.

Residents have been urged to stay alert and be prepared in case further action is needed.

After authorities confirmed two fatalities, reports are now emerging of another firefighter being injured in the Coeur d’Alene shooting.

According to the International Association of Fire Fighters (IAFF), a firefighter remains in surgery after two firefighters were killed.

The third firefighter was critically injured when a sniper opened fire on crews responding to the blaze on Canfield Mountain.

The injured firefighter is still undergoing surgery, the union said in a post on X.

The IAFF, which represents emergency workers across the US and Canada, described the incident as a “heinous act of violence”.

Kootenai County sheriff Robert Norris says that there is at least one active shooter firing at law enforcement with a high-powered rifle.

“If these individuals are not neutralised quickly, this is going to be a likely a multi-day operation,” he said.

He said that officers had reported bullets coming in from different directions.

“We are actively taking sniper fire as we speak,” said Sheriff Norris from the Kootenai County Sheriff's Office in a press conference.

“We don’t know how many suspects are up there, and we don’t know how many casualties there are,” he said earlier.

He said that the shooter or shooters showed “no sign of wanting to surrender”.

Two firefighters were fatally shot while responding to a brush fire near Coeur d’Alene in western Idaho.

Officials say they were ambushed by one or more shooters hiding in dense brush and firing from multiple positions, possibly with high-powered rifles.

Firefighting efforts have been halted due to the threat, and a shelter-in-place order is in effect for the residents.

Governor Brad Little condemned the attack, calling it a “heinous assault” on “brave firefighters”.