Ukrainian lawmakers applaud a televised address by the President of the European Parliament Martin Schulz (on screen) in the Ukrainian parliament on Tuesday in Kiev. The parliament voted to strengthen trade ties with the EU, but not until 2016. Sergey Dolzhenko/EPA/Landov hide caption

itoggle caption Sergey Dolzhenko/EPA/Landov

Pro-Russian militants take a break at a checkpoint close to where shelling continued Sunday between pro-Russian forces and the Ukrainian army in the village of Olenivka, some 30 kms south of Donetsk on the way to Mariupol, eastern Ukraine. Philippe Desmazes/AFP/Getty Images hide caption

itoggle caption Philippe Desmazes/AFP/Getty Images

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

A convoy of Russian trucks crosses the Ukrainian border at the Donetsk-Izvarino custom control checkpoint as Ukrainian refugees look on, Saturday. Russia says the trucks are carrying aid; Ukrainian officials say they don't know what's inside. SERGEI VENYAVSKY/AFP/Getty Images hide caption

itoggle caption SERGEI VENYAVSKY/AFP/Getty Images

People wait for a bus in the empty streets of Donetsk on Tuesday. The city's population, which was 900,000, is now down to around 300,000. It is beginning to return to normal following a cease-fire, which was signed last week and is mostly holding. But residents are divided over the region's future. Spencer Platt/Getty Images hide caption

itoggle caption Spencer Platt/Getty Images

Mothers and wives of Russian paratroopers captured in Ukraine wait for information outside their base in Kostroma, Russia. Russia's military has been challenged to explain an upsurge in dead and missing soldiers from its elite units. Dmitry Serebryakov/AFP/Getty Images hide caption

itoggle caption Dmitry Serebryakov/AFP/Getty Images

A Ukrainian army checkpoint burns on the road to Russia after loud explosions were heard on the outskirts of Mariupol late Saturday. Philippe Desmazes/AFP/Getty Images hide caption

itoggle caption Philippe Desmazes/AFP/Getty Images

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