The fourth U.S. Army soldier who went missing in Lithuania last week during a training exercise was found dead on Tuesday, the Army said in a statement.

“The Soldier was found after a search by hundreds of rescue workers from the U.S. Army, U.S. Navy, Lithuanian Armed Forces, Polish Armed Forces, Estonian Armed Forces, and many other elements of the Lithuanian government and civilian agencies,” the statement said.

On Monday, the U.S. Army confirmed the deaths of the other three soldiers.

Maj. Gen. Christopher Norrie, 3rd Inf. Div. commanding general, in a statement on Monday said: “Our hearts are heavy with a sorrow that echoes across the whole Marne Division, both forward and at home. We stand in grief with the families and loved ones of these extraordinary ‘Dogface Soldiers’ during this unimaginable time.”

Maj. Gen. Curtis Taylor, commander of Task Force Iron and the 1st Armored Division, said it is “a very sad and tragic day.”

“The loss of these soldiers weighs heavy on me, the hearts of all Task Force Iron service members, and the 3rd Infantry Division. Our thoughts and prayers are with the families and loved ones of these brave Soldiers,” he said in a statement.

“I’d like to personally commend the heroic efforts of the search parties, and especially our Lithuanian allies who were instrumental in the recovery efforts.

“Their courage and commitment to this operation will always be remembered and demonstrates the strong relationship between our countries.”

U.S. Soldiers on Training Exercise in Lithuania

The soldiers, all from 1st Brigade, 3rd Infantry Division, were conducting tactical training when they went missing in Lithuania, a Baltic ally in the NATO defense alliance.

They were on an exercise at the General Silvestras Žukauskas training ground in the town of Pabradė when they, along with their vehicle, were reported missing in the early hours of March 25, the U.S. Army said.

Hundreds of Lithuanian and U.S. soldiers and rescuers took part in the search through the thick forests and swampy terrain around Pabradė, which lies 10 kilometers (6 miles) west of the border with Belarus.

The M88A2 Hercules armored vehicle was discovered on Wednesday submerged in 4.5 meters (15 feet) of water.

U.S. Troops in NATO’s Lithuania

About 1,000 U.S. soldiers are stationed in Lithuania on a rotational basis.

Lithuania and Poland bracket the Russian exclave of Kaliningrad, where Moscow bases its Baltic Sea naval fleet, and both NATO countries share significant land borders with Belarus, Moscow’s key ally.

NATO has been fortifying its eastern flank, close to Russia, as alliance members ring alarm bells about Moscow’s potential ambitions in the Baltic. Lithuania and other Baltic states have led NATO’s efforts to sharply increase defense spending by allies.

But there are deepening concerns about the plans for the tens of thousands of U.S. military personnel stationed on the Continent as the Trump administration pulls back from Europe to shift its strategic focus to China.

Lithuanian Foreign Minister Kęstutis Budrys said during a visit to Washington, D.C., that Vilnius was pleased to host U.S. rotational battalions in the country and was ready to accept more American troops, according to a readout published by the Foreign Ministry.

This article uses reporting by the Associated Press.