Zachary Gallegos, 23, stands guard outside the Armed Services Recruiting Center on Thursday in Sioux Falls, South Dakota. The Pentagon has asked such self-appointed "armed citizens" to leave, citing security concerns. Kevin Burbach/AP hide caption

itoggle caption Kevin Burbach/AP

Marine Corps Commandant Gen. Joseph Dunford Jr. testifies Thursday during his Senate Armed Services Committee confirmation hearing to become the chairman of the Joint Chiefs of Staff. Cliff Owen/AP hide caption

itoggle caption Cliff Owen/AP

U.S. Bradley fighting vehicles take part in a joint exercise with Georgia at a military base near Tbilisi. Bradleys would be deployed to NATO member states in Eastern Europe and the Baltics if a Pentagon proposal is approved. Zurab Kurtsikidze/EPA/Landov hide caption

itoggle caption Zurab Kurtsikidze/EPA/Landov

Edwin Hopkins with his mother, Alice, and father, Frank Jr. Hopkins was killed aboard the USS Oklahoma during the Japanese bombing of Pearl Harbor, but his remains never were identified. Courtesy Tom Gray hide caption

itoggle caption Courtesy Tom Gray

A gravestone identifying the resting place of seven unknowns from the USS Oklahoma is shown at the National Memorial Cemetery of the Pacific in Honolulu. The Pentagon says it will disinter and try to identify the remains of up to 388 unaccounted for sailors and Marines killed when the ship capsized in the 1941 Japanese bombing of Pearl Harbor. Audrey McAvoy/AP hide caption

itoggle caption Audrey McAvoy/AP

Vice President Biden swears in Ashton Carter, as the new Secretary of Defense's wife, Stephanie, holds the Bible for a ceremony in the White House Tuesday. Shawn Thew/EPA/Landov hide caption

itoggle caption Shawn Thew/EPA/Landov

An A-18C Hornet attached to Strike Fighter Squadron (VFA) 87, prepares to launch from the flight deck of the aircraft carrier USS George H.W. Bush (CVN 77) to conduct strike missions against Islamic State group targets. Robert Burck/AP hide caption

itoggle caption Robert Burck/AP