New Delhi, June 30 -- Three firefighters killed over the weekend in a wildfire along the Colorado-Utah border were trying to shield themselves from flames by deploying tent-like shelters when they were overcome, authorities said.

The firefighters were part of a specialized crew that goes into remote areas by helicopter to quickly put out new and rapidly escalating wildfires, federal officials said Monday.

Their deaths Saturday came almost 13 years to the day since an elite crew of 19 wildland firefighters died when they were trapped in a steep canyon in Yarnell, Arizona.

Like this weekend's victims, the men in Arizona tried to deploy emergency shelters that are a "last resort" for firefighters when there's no other way out. Investigato...