Nineteen firefighters were killed in Arizona on Sunday battling a blaze that had started with a lightning strike on Friday and became a fast-moving blaze that advanced by hot, dry conditions.

According to Fox News, the 19 firefighters were members of an elite crew called in to battle the region's worst fires. Chief of Fire for Prescott, Dan Fraijo, said the firefighters were part of the city's fire department.

The firefighters were battling an almost 2,000 acre wildfire near Yarnell and had been forced to deploy their emergency fire shelters - tent-like structures meant to shield them from flames and heat - when they were caught in the fire.

In a statement, Arizona Governor Jan Brewer said "this is as dark a day as I can remember. "

President Obama, who is traveling in Africa, also released a statement praising the firefighters as "heroes - highly skilled professionals who, like so many across our country do every day, selflessly put themselves in harm's way to protect the lives and property of fellow citizen's they would never meet."