A B-1B bomber crashed on a runway at Ellsworth Air Force Base in the second accident involving one of the long-range strategic jets in two weeks, officials said Friday.

The plane crashed as it came in for a landing at about 10:40 p.m. Thursday, but the crew of four ejected and safely parachuted from the plane, officials said.The B-1B did not hit any buildings, and no one on the ground was known to be injured, said Lt. Fred Brown of the Rapid City Police Department. "It is possible that it came in too low and hit a power pole," he said.

The crew was taken to the base hospital as a precaution, but all were in good condition, Maj. Joseph B. Saxon, Ellsworth's public affairs officer, said at a news conference Friday morning. He said the cause of the crash was unknown.

The crash came two days after officials reported that the Air Force had inspected and cleared more than two-thirds of the 98 B-1B bombers, which were grounded following a crash last week that destroyed one of the long-range planes in Texas.

On Nov. 8, a B-1B crashed and burned in a field near Dyess Air Force Base in west Texas. It was the second accident to claim one of the bombers in 14 months. In that crash, the crew of four ejected and survived.