Estonian President Toomas Hendrik Ilves climbs up the hull of an M1A2 Abrams Battle Tank from the 3rd Infantry Division's 2nd Battalion, 7th Infantry Regiment out of Fort Stewart, Ga.,during a visit to Operation Siil held in Johvi, Estonia, May 9, 2015. Soldiers from 3rd Infantry Division and the 173rd Airborne Brigade out of Grafenw??hr, Germany, are currently deployed throughout Europe as part of Operation Atlantic Resolve. (Brooks Fletcher/U.S. Army)

Korean War veteran Walter Derebeew, who escaped from Russia during World War II, attends the historic aircraft sweep over the National Mall in Washington, D.C. during the Arsenal of Democracy Flyover May 8, 2015, to commemorate the 70th anniversary of the World War II victory in Europe. (Bernardo Fuller/U.S. Army)

The crew of an M1A2 Abrams Main Battle Tank fires the main gun at a target during the night portion of gunnery training May 8, 2015, at the Camp Konotop, Poland, Range Complex. The soldiers, assigned to 7th Infantry Regiment, 1st Armored Brigade Combat Team, 3rd Infantry Division, are taking part in Operation Atlantic Resolve. (Spencer Garrison/U.S. Army)

Sgt. Troy McFall, 316th Engineer Company, helps Spc. Robert Waggoner, 412th Theater Engineer Command, align his unit awards before the sergeant?s major board during the 2015 U.S. Army Reserve Best Warrior Competition at Fort Bragg, N.C., on May 7, 2015. The competition will determine the top noncommissioned officer and junior enlisted soldier who will represent the Army Reserve in the Department of the Army Best Warrior Competition later this year at Fort Lee, Va. (Felix R. Fimbres/U.S. Army)

Soldiers with the Estonian Defense Forces conduct an artillery live fire on May 8, 2015, at the Central Training Area. During the training, the fire teams were tested for accuracy as well as speed. (Juana M. Nesbitt/U.S. Army)

Paratroopers from the 173rd Airborne Brigade parachute into the opening ceremony of Exercise Noble Partner on May 10, 2015. Noble Partner is a U.S. Army Europe-Georgia exercise in support of Georgia's contribution to the NATO Response Force. (173rd Airborne Brigade)

A convoy of M1A2 Abrams Battle Tank from 7th Infantry Regiment, 1st Armored Brigade Combat Team, 3rd Infantry Division out of Fort Stewart, Ga., rolls through the town of M??etaguse, Estonia, during Operation Siil held in Johvi, Estonia, on May 10, 2015. They are deployed as part of Operation Atlantic Resolve, a multinational partnership focused on joint training and security cooperation between the U.S. and NATO allies. (Brooks Fletcher/U.S. Army)

Members of the 388th Chemical Biological Radiological Nuclear Company participate in a Mass Casualty Decontamination training event during Battle Assembly at Fort McCoy and Volk Field, Wis., on May 8-10, 2015. Catherine Threat/U.S. Army (Catherine Threat/U.S. Army)

A machine gunner with 3rd Battalion (Airborne) 509th Infantry Regiment reports his status during a Combined Arms Maneuver Live Fire Exercise at Joint Base Elmendorf-Richardson, Alaska, May 8, 2015. The exercise was part of the 4th Infantry Brigade Combat Team (Airborne), 25th Infantry Division exercise Spartan Phoenix. (Daniel Love/U.S. Army)

An Estonian soldier throws a dummy grenade at British forces after the defense of Oandu, Estonia, during Operation Siil, May 12, 2015. For the exercise, British and American forces were fighting alongside and against Estonian forces. Operation Siil is the largest training exercise ever held in Estonia and features more than 12,000 soldiers from six nations. \ (Joshua S. Brandenburg/U.S. Army)