Three firefighters were killed and two others were injured while responding to wildfires along the Utah-Colorado border, the U.S. Wildland Fire Service reported.

The incident happened while crews were tackling the Knowles and Gore fires on Saturday. Authorities said the two fires later merged into the larger Snyder Fire, which grew quickly and was mapped at about 28,000 acres.

Officials also said the firefighting teams included locally based federal firefighters working as part of a multi-agency response. Two of the five firefighters involved in the incident were transported to a hospital with serious injuries, and the service said all were part of the same operational effort.

As the fire expanded, officials began issuing pre-evacuation orders and closing or restricting access to nearby areas. Colorado Governor Jared Polis declared a disaster emergency and authorized help from the National Guard, while Utah officials also activated emergency measures to support firefighting operations.