US military grounds V-22 Osprey aircraft after Japan crash

File photo: A U.S. Bell Boeing V-22 Osprey helicopter lands on the USS Mesa Verde ship during the Northern Coasts 2023 exercise in the Baltic Sea, September 18, 2023. REUTERS/Janis Laizans/File photo

(Reuters) -The United States said on Wednesday it was grounding its military fleet of V-22 Osprey aircraft after a fatal crash last week off the coast of Japan that killed eight people onboard.

"Preliminary investigation information indicates a potential materiel failure caused the mishap, but the underlying cause of the failure is unknown at this time," U.S. Air Force Special Operations Command (AFSOC) said in a statement.