Three U.S. Army soldiers were found dead in Lithuania on Monday, nearly a week after the armored vehicle they had been using during a training mission became stuck in a deep and muddy bog, the Army said.

Search and recovery operations for a fourth soldier who was also in the vehicle continued on Monday, the Army said.

The 70-ton vehicle was pulled out of the bog early on Monday morning, the Army said. For days, hundreds of people, including technical experts and U.S. Navy divers, had worked to solve the complex engineering challenge of recovering the vehicle from the bog. The operation required excavators, pumps and other construction equipment.

The soldiers were reported missing on Tuesday after they did not return from a training mission, according to the U.S. military. Their vehicle, an M88 Hercules, was found submerged in the bog on Wednesday.

The missing soldiers, from the First Brigade, Third Infantry Division, were training near Pabrade, a city in eastern Lithuania near the border with Belarus, a close ally of Russia and a stalwart supporter of its war in Ukraine.

Maj. Gen. Christopher Norrie, the Third Infantry Division’s commanding general, said in a statement on Monday that “the search isn’t finished until everyone is home.”

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