The incident, which occurred around 5:50 p.m. local time, happened during a training mission with a crew of four, Ellsworth Air Force Base said in a Facebook post.
"There were four aircrew on board," according to the statement. "All four ejected safely."
The base said in the public statement that a board of officers will investigate the incident. Additional details were not immediately available. Radio chatter between first responders posted to the social media site X described reports of an "active fire" and an "explosion" at the base.
The B-1B Lancer has been in service with the Air Force since the mid-1980s, and about 60 of the aircraft are left in the fleet, which is divided between Dyess Air Force Base in Texas and Ellsworth near Rapid City, South Dakota. Each one costs roughly $317 million, according to a service fact sheet.
The B-1B Lancer is a long-range bomber that at one point was nuclear capable but hasn't been since 2007.
"The United States eliminated the nuclear mission for the B-1 in 1994," an Air Force fact sheet detailed. "Even though the Air Force expended no further funding to maintain nuclear capabilities, the B-1 was still considered a heavy bomber equipped for nuclear armament until 2007."
Thursday evening's crash marks the latest incident involving a B-1B Lancer. In 2022, Military.com reported that a B-1B Lancer bomber at Dyess Air Force Base in Texas caught fire, sending two people to the hospital.
Between 1984 and 2021, the latest data available from the service, there have been a total of 29 Lancer Class A mishaps -- the term used for the deadliest and most expensive incidents -- and 11 people have been killed.
The Air Force unveiled its latest bomber, the B-21 Raider, in late 2022. It's the first new bomber in the American military's fleet in more than 30 years and aims to eventually replace the B-2 Spirit bomber, as well as the B-1B Lancer, sometime in the 2030s.
The Pentagon plans to build 100 B-21s, more than the Air Force's B-2 and B-1B Lancer fleets combined, with an average unit cost for each bomber of nearly $700 million, according to a service fact sheet.