U.S. and Lithuanian troops are struggling to recover four missing American soldiers after their armored vehicle sank in a swamp during a training exercise in Lithuania.

The M88 Hercules was found submerged in 15 feet of water, but efforts to extract it have been slow due to the marshy terrain.

Cranes, pumps, and gravel have been brought in, and a U.S. Navy dive crew and Polish engineers are joining the operation, the Associated Press has reported.

Officials warn the recovery will take time, but they remain committed to bringing the soldiers home.

Written by B.C. Begley