SIOUX FALLS, S.D. — A B-1B bomber crashed in a remote area of southeastern Montana on Monday, but its four crew members survived after ejecting from the South Dakota-based aircraft, Air Force officials said.

The two pilots and two weapons system officers ejected before the bomber crashed near Broadus, Mont., said Col. Kevin Kennedy, commander of the 28th Bomb Wing.

Kennedy said the crew members were taken by ambulance and air to South Dakota hospitals in Rapid City and Spearfish. None of them suffered life-threatening injuries, he said.

“No one likes to lose an aircraft. It’s bittersweet that we did,” Kennedy said during a news conference Monday afternoon. “Luckily, all four air crew are safely recovered.

The plane was based out of South Dakota’s Ellsworth Air Force Base, one of only two bases in the U.S. that have B-1B crews. Kennedy said Ellsworth has temporarily shut down flights until his maintenance and operations group commanders can ensure that they can safely resume.

He said the Air Force will conduct a thorough investigation to determine the cause of the accident, which happened about 170 miles southeast of Billings, Mont.

The B-1B Lancer is a swing-wing bomber intended for high-speed, low-altitude penetration missions. The only other base with B-1B crews is Dyess Air Force Base in Abilene, Texas.

Broadus, Mont., is a town within the Powder River Training Complex, an 8,300-square-mile block of airspace centered just northwest of where South Dakota, Wyoming and Montana meet.

An Air Force plan to more than triple the airspace, which is used in training exercises for B-1B and B-52 bombers based in the Dakotas, has been in the works for more than six years. The Air Force wants to add three “military operation areas” to create a fly space of about 27,500 square miles — an area larger than West Virginia.

The last time a B-1B was destroyed in a crash was on Dec. 12, 2001, when a bomber involved in the war in Afghanistan slammed into the Indian Ocean near the island of Diego Garcia, said Air Force Lt. Col. Allen Herritage. A cause has never been determined. The crew had reported having difficulty controlling the bomber. All four crewmen ejected safely, including the pilot and co-pilot, who were from Ellsworth.

At the start of the war in Afghanistan, B-1Bs and B-52s were making almost daily bombing runs over the country and began pounding al-Qaida mountain hide-outs in the Tora Bora region.

In April 2008, an Ellsworth B-1B bomber caught fire after landing at al-Udeid Air Base in Qatar. The crew members all escaped safely. A month earlier, an Ellsworth B-1B collided with two emergency-response vehicles during landing after reporting an in-flight emergency at Andersen Air Force Base in Guam.

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Associated Press researcher Jennifer Farrar in New York and AP writer Robert Burns in Washington contributed to this story.