Crews were searching for survivors, CNN reported.

Air Force Capt. Joel Stark, a spokesman for Andersen Air Force Base in Guam, said rescuers with the U.S. Coast Guard and the U.S. Navy were searching an area of the Pacific Ocean about 30 miles northwest of Guam where the plane is believed to have crashed.

The B-52H Stratofortress, based at Barksdale Air Force Base in Louisiana, was in Guam as part of a four-month rotation, Stark said.

A B-52 from Andersen Air Force Base was to fly over crowds as part of Liberation Day, commemorating the U.S. capture of Guam from Japan in 1944, Stark said. It was unclear whether the plane that crashed was one scheduled to perform the flyover.