Three of the U.S. Army soldiers who went missing in Lithuania have been found dead in their armored vehicle that was pulled from a swampy area.

The bodies of the three soldiers were recovered after a massive six-day effort by U.S., Polish and Lithuanian armed forces and authorities to dig the M88 Hercules vehicle out of a peat bog at the expansive General Silvestras Žukauskas training ground in the town of Pabradė.

The soldiers were on a tactical training exercise when they and their vehicle were reported missing early Tuesday, the Army said.