Sgt. Samantha Melanson, assigned to 15th Engineer Battalion, rappels from a 55-foot tower during an air assault course at the 7th Army Joint Multinational Training Command's Grafenwoehr Training Area, Germany, June 8, 2015. (Markus Rauchenberger/U.S. Army)

U.S. soldiers rappel from a UH-60 Black Hawk during an air assault course at the 7th Army Joint Multinational Training Command's Grafenwoehr Training Area, Germany, June 9, 2015. (Markus Rauchenberger/U.S. Army)

Army veteran Frank Barroqueiro, of Gainesville, Ga., counts up his score during archery training for the 2015 Department Of Defense Warrior Games archery competition at Fort Belvoir, Va., June 9, 2015. (Jamill Ford/U.S. Army)

Capt. Emilee Alms, right, a veterinarian with the 407th Civil Affairs Battalion, 308th Civil Affairs Brigade, and Spc. Anna Peterson, perform a vaccination during a veterinary civil assistance event at Cheyenne River Indian Reservation, S.D., in support of Golden Coyote training exercise June 9, 2015. (Tracy McKithern/U.S. Army)

Staff Sgt. Dirk Maushake, a German army unmanned aerial vehicle operator prepares to launch a UAV Aladin during exercise Saber Strike, in Rukla, Lithuania June 10, 2015. (Jarred Woods/U.S. Army)

Soldiers from the Norwegian Army???s 2nd Infantry Battalion and the Estonian Land Forces??? Kuperjan conduct an after-action review following a situational training exercise during the Saber Strike 2015 Distinguished Vistor Day, held in Adazi, Latvia, June 10, 2015. (Brooks Fletcher/U.S. Army)

German army soldiers assigned to 5th Company, Jager Battalion as forward observers, hide in their camouflaged foxhole during the second day of multinational training at the Great Lithuanian Hetman Jonusas Radvila Training Regiment, in Rukla, Lithuania, June 11, 2015. (James Avery/U.S. Army)

A soldier drags a mock casualty in a test of his first-aid skills while in combat conditions as part of the Best Warrior Challenge on June 9, 2015, during Pacific Army Week in Hawaii. (Jaquetta Gooden/U.S. Army)