Estonian President Toomas Hendrik Ilves (left), with intelligence officer Eston Kohver in 2010. Kohver was arrested by Russian police on spying charges, but Estonian officials called it an illegal kidnapping. AP hide caption

itoggle caption AP

President Obama stands alongside British Prime Minister David Cameron, center left, NATO Secretary General Anders Fogh Rasmussen, second left, Croatian President Ivo Josipovic, left, Romanian President Traian Basescu, right, and RAF Group Captain David Bentley, second right, during a flypast at the NATO summit at the Celtic Manor Resort in Newport, Wales on Friday. Jon Super/AP hide caption

itoggle caption Jon Super/AP

President Obama sits with (from left) French President Francois Hollande; Ukrainian President Petro Poroshenko; British Prime Minister David Cameron; German Chancellor Angela Merkel; and Italian Prime Minister Matteo Renzi as they meet about Ukraine Thursday at the NATO summit at Celtic Manor in Newport, Wales. Charles Dharapak/AP hide caption

itoggle caption Charles Dharapak/AP

Pro-Russian rebels prepare their weapons in the eastern city of Donetsk on Aug. 31. Russia's role in Ukraine has raised tensions between Russia and NATO to their highest level since the Soviet breakup more than two decades ago. Mstislav Chernov/AP hide caption

itoggle caption Mstislav Chernov/AP

A pro-Russian rebel walks in a passage at a local market damaged by shelling in Petrovskiy district in the eastern Ukrainian town of Donetsk. Mstislav Chernov/AP hide caption

itoggle caption Mstislav Chernov/AP

Masked pro-Russian activists guard a barricade outside the regional state building seized by separatists in the eastern Ukrainian city of Donetsk Saturday. Pro-Russian forces holding a group of international observers have accused them of being "NATO spies." Alexander Khudoteply/AFP/Getty Images hide caption

itoggle caption Alexander Khudoteply/AFP/Getty Images

Ousted Ukrainian President Viktor Yanukovych during an interview with The Associated Press, in Rostov-on-Don, Russia, on Wednesday. He said he hoped to persuade Russian President Vladimir Putin to return Crimea to Ukraine. Ivan Sekretarev/AP hide caption

itoggle caption Ivan Sekretarev/AP

NATO Secretary General Anders Fogh Rasmussen looks on at the start of a NATO foreign ministers meeting at the Alliance headquarters in Brussels on Tuesday. Francois Lenoir/Reuters/Landov hide caption

itoggle caption Francois Lenoir/Reuters/Landov

An Afghan security officer runs toward the scene of Friday's bombing in Kabul. Three NATO personnel were killed and at least six Afghan civilians were wounded. Omar Sobhani /Reuters /Landov hide caption

itoggle caption Omar Sobhani /Reuters /Landov

Afghan National Army Commandos attend their graduation ceremony in Kabul in July. Foreign combat troops are set to leave Afghanistan by the end of 2014 after handing over all security responsibilities to Afghan forces. S. Sabawoon/EPA/Landov hide caption

itoggle caption S. Sabawoon/EPA/Landov

Anti-war protesters rally outside Downing Street in London on Wednesday. Britain's Parliament rejected the country's involvement in any military action against Syria. The U.K. government had been among those seeking a strong response to the alleged use of chemical weapons in Syria. Matt Dunham/AP hide caption

itoggle caption Matt Dunham/AP

The scene Thursday in Kabul, Afghanistan, after a suicide bomber attacked a NATO convoy. Zhao Yishen /Xinhua /Landov hide caption

itoggle caption Zhao Yishen /Xinhua /Landov

A suicide bomber struck a convoy of buses today in Kabul, killing at least 12 people — mostly foreigners. Massoud Hossaini /AFP/Getty Images hide caption

itoggle caption Massoud Hossaini /AFP/Getty Images

Aug. 13: At Dover Air Force Base in Delaware, the remains of Marine Lance Cpl. Gregory T. Buckley are carried during a dignified transfer. He was killed in a "green on blue" attack. Mark Wilson/Getty Images hide caption

itoggle caption Mark Wilson/Getty Images

President Obama shakes hands with with Afghan President Hamid Karzai during their meeting at the NATO Summit in Chicago on Sunday. The summit, which continues Monday, is focusing heavily on Afghanistan's future. Pablo Martinez Monsivais/AP hide caption

itoggle caption Pablo Martinez Monsivais/AP