The suspected shooter was found dead with a firearm on Canfield Mountain in Kootenai County – a popular park and hiking area – following an hours-long standoff as the fire raged.

“Based on preliminary information, we believe that was the only shooter,” Kootenai County’s sheriff Robert Norris told a news conference yesterday evening, adding, “there is no threat to the community at this time”.

Norris said authorities believed the fire was “intentional”, without providing details on the shooter’s identity.

“We do believe that the suspect started the fire and that it was an ambush, and it was intentional,” he told reporters.

“These firefighters did not have a chance.”

About 300 law enforcement officers were deployed to the scene.

Two firefighters were shot dead, while a third was wounded and taken to the hospital for surgery.

“He is fighting for his life, but he’s in stable condition,” Norris said.

The attack was carried out with high-powered rifles, the sheriff told an earlier news conference.

Local TV footage showed dense white smoke billowing above a hilly, forested area.

Authorities warned yesterday evening that the wildfire was still active.

Heartbroken

Local fire chief Pat Riley said he was “heartbroken” by the attack.

He told local TV station KHQ that no evacuations had been ordered, though the fire was still burning.

Asked if there was a concern about the fire spreading, he told KHQ: “Yes there is. To what extent, I can’t say, because we can’t get people to where the fire’s at.”

Serious gun violence is common across the US, where many states have few barriers to the purchasing of firearms, despite widespread support for greater gun control.

There have been 189 mass shootings in the US this year, according to the Gun Violence Archive – which it defines as four or more people shot.

Idaho governor Brad Little described the attack as a “heinous direct assault on our brave firefighters”.

He said in a social media post he was “heartbroken” by the attack.