A B-1 bomber with the Air Force's 28th Bomb Wing at Ellsworth Air Force Base, S.D., crashed Monday in Broadus, Mont.
The two pilots and two weapons officers on board ejected. Crew members did sustain injuries, but the statement from the Air Force did not say how many were injured, or the nature of the injuries.
The B-1 Lancer was flying a routine training mission prior to the crash. Ellsworth officials said the Air Force had launched an investigation to determine the cause.
"We are actively working to ensure the safety of the crew members and have sent first responders to secure the scene and work closely with local authorities at the crash site,” said Col. Kevin Kennedy, 28th Bomb Wing commander in a statement. "Right now all of our thoughts and prayers are with the crews and their families."
No civilians on the ground were injured or killed in the crash.
The Air Force had 65 B-1 Lancers in its bomber fleet. During the Cold War, the B-1 carried nuclear weapons before it was converted to a strictly conventional bomber in the 1990s.
Ellsworth officials didn't say whether the bomber was carrying weapons at the time of the crash.
The aircraft, built by Boeing, has a 134-foot wingspan, a 30,000 foot ceiling, and can fly Mach 1.2 at sea level, according to Air Force statistics. It has served a prominent role in the Afghanistan war flying bombing mission over the past decade.