A team of 19 elite firefighters have been killed while battling a fast-moving wildlife in Arizona.
The firefighters, 18 of whom are believed to have been from the specially-trained Granite Mountain Hotshots, were caught by the blaze near the central town of Yarnell.
They were hailed as "heroes" by US President Barack Obama, who said they "selflessly put themselves in harm's way to protect the lives and property of fellow citizens they would never meet".
The firefighters were confronted by a fast-moving blaze
The wildlife is the deadliest involving fatalities to fire crews since a blaze at Griffith Park, Los Angeles, nearly 70 years ago, according to figures from the National Fire Protection Association.
"We're devastated," Prescott Fire Chief Dan Fraijo said. "We just lost 19 of the finest people you'll ever meet."
Hotshot crews often hike long distances and carry chainsaws and backpacks filled with heavy gear to build lines of protection between people and fires.
They were forced to deploy their emergency shelters when confronted by the blaze.
"One of the last fail safe methods that a firefighter can do under those conditions is literally to dig as much as they can down and cover themselves with a protective … fire-resistant material," Mr Frajo said.
"The hope at least is that the fire will burn over the top of them and they can survive it. Under certain conditions there's usually only sometimes a 50% chance that they survive.
"It's an extreme measure that's taken under the absolute worst conditions."
Strong winds and low humidity allowed the blaze to spread quickly
Messages of condolence for the families of those who died have been left on a Facebook page set up in their memory.
"This awful tragedy really reminds us how dangerous a job firefighters have," wrote Lakyn Spivey. "They go to work every day to save lives, not knowing if they themselves will be coming home that day."
Natalie Minafore added: "My son is a firefighter and I cannot imagine the heartache these families must feel. These men are heroes."
Arizona Governor Jan Brewer said the state had endured "as dark a day" as she could remember.
"It may be days or longer before an investigation reveals how this tragedy occurred, but the essence we already know in our hearts is that fighting fires is dangerous work," she said.
Hundreds of homes have been destroyed by the fire
According to local newspaper The Republic, around 250 homes - roughly half the town of Yarnell - were destroyed by the wildlife.
Federal government is assisting and President Obama pledged to provide state and local officials with all the support they neeed.
The blaze, which broke out on Friday, is thought to have been triggered by a lightning strike.
Hot, gusty winds blew the fire out of control over the weekend, as flames ripped through 2,000 acres of dry land.
RIP to those lost X.
