ANDERSEN AIR FORCE BASE, Guam, July 23 (UPI) -- All six airmen aboard a U.S. Air Force B-52 bomber died when it crashed into the Pacific Ocean off Guam this week, Air Force officials said late Wednesday.

After three days of searching for survivors, the effort had switched to one of recovery, Stars and Stripes reported.

"Losing this bomber crew has been a tragedy felt by everyone here and across the Air Force," Brig. Gen. Doug Owens, 36th Wing commander at Andersen Air Force Base in Guam, said in a statement. "Our deepest sympathies and prayers are with the families of these Airmen as we continue to support them during this difficult time."

The only crew member identified by the military was Maj. Christopher Cooper. The names of the other victims were withheld pending family notification. A family member had identified one of the victims as Col. George Martin, a doctor assigned to Andersen's medical unit, Stars and Stripes said.

Five of the six airmen were stationed at Barksdale Air Force Base in Louisiana and were assigned to Guam as part of a routine rotation.

The cause of the crash was being investigated. The bomber carried no weapons when it went down about 30 miles out to sea Monday.