President Barack Obama, followed by his daughter Malia, walks down the steps of Marine One at Andrews Air Force Base, Md., Saturday, Aug. 9, 2014, as they go to board Air Force One en route to Martha's Vineyard. President Obama is opening a two-week summer vacation in Martha's Vineyard just as the U.S. is engaged in airstrikes against Islamic militant targets in Iraq. (AP Photo/Susan Walsh)
President Barack Obama second from left, walks from Marine One with Vice Commander of the 89th Airlift Wing at Andrew Air Force Base Col. Preston Williamson IV, third from left, followed by his daughter Malia Obama, left, first lady Michelle Obama, second from right and Christine Williamson, to board Air Force One at Andrews Air Force Base, Md., Saturday, Aug. 9, 2014.
Kurdish Peshmerga fighters take cover during airstrikes targeting Islamic State militants near the Khazer checkpoint outside of the city of Irbil in northern Iraq, Friday, Aug. 8, 2014.
Kurdish Peshmerga fighters stand guard as smoke rises after airstrikes targeting Islamic State militants near the Khazer checkpoint outside of the city of Irbil in northern Iraq, Friday, Aug. 8, 2014. The Iraqi Air Force has been carrying out strikes against the militants, and for the first time on Friday, U.S. war planes also directly targeted the group, which controls large areas of Syria and Iraq. (AP Photo/Khalid Mohammed)
Iraqi Kurdish Peshmerga fighters take position on the front line in Khazer, near the Kurdish checkpoint of Aski kalak on August 8, 2014 (AFP Photo/Safin Hamed)
These photos provided by the U.S. Defense Department shows pallets of bottled water are loaded aboard a U.S. Air Force C-17 Globemaster III aircraft in preparation for a humanitarian airdrop over Iraq Aug. 8, 2014. Airmen with the 816th Expeditionary Airlift Squadron airdropped 40 bundles of water for displaced citizens in the vicinity of Sinjar, Iraq. American planes conducted a second airdrop of food and water early Saturday for those trapped in the Sinjar mountains, said Pentagon chief spokesman Rear Adm. John Kirby. (AP Photo/U.S. Air Force, Staff Sgt. Vernon Young Jr.)
Kurdish Peshmerga fighters walk toward the front line with militants from the extremist Islamic State group, at the Khazer checkpoint outside of the city of Irbil in northern Iraq, Friday, Aug. 8, 2014.
Kurdish Peshmerga fighters detain a man suspected as a militant for the Islamic State group, as airstrikes target Islamic State militants near the Khazer checkpoint outside of the city of Irbil in northern Iraq, Friday, Aug. 8, 2014.
St. Louis County Police investigate a situation after an armed man entered an hospice building demanding drugs on Saturday, Aug. 9, 2014, in St. Louis County, Mo. Officer Brian Schellman says no one was hurt and said it "looks like a failed robbery attempt." Schellman says the man was armed with a handgun, walked into the de Greeff Hospice House and directed a nurse to take him to where the narcotics were. The nurse started walking with the man toward the back of the building, and then ran. Schellman says the armed man ran out of an unlocked door likely before police arrived. (AP Photo/St. Louis Post-Dispatch, Huy Mach
Smoke rises in Gaza City after an Israeli airstrike Saturday, Aug. 9, 2014. (AP Photo/Dusan Vranic)