U.S. Navy divers are pushing through mud in a flooded Lithuanian bog in an effort to excavate a submerged armored vehicle and locate four missing U.S. soldiers, Army officials said.

Hundreds of troops and emergency workers are racing to find four US soldiers who went missing during a training mission near Lithuania’s border with Belarus, the US Army said Thursday, after their armored vehicle was found submerged in a body of water.

U.S. Army Europe and Africa divisions said the M88 Hercules Armored vehicle the soldiers were operating during a training exercise was located in Lithuania. It was found submerged in a body of water in the training area. The four soldiers, who call Fort Stewart home, however, have not been located.