A smoldering rebel APC near the city of Lisichansk, Luhansk region, eastern Ukraine, on Saturday. Fighting farther south, near the city of Donetsk, has prevented investigators from reaching the wreckage of MH17. Dmitry Lovetsky/AP hide caption

itoggle caption Dmitry Lovetsky/AP

Ukrainian troops camouflage their multiple rocket launcher at a checkpoint in Kryva Luka, in eastern Ukraine, earlier this month. The U.S. says Russia is planning to provide similar systems to the rebels. Evgeniy Maloletka/AP hide caption

itoggle caption Evgeniy Maloletka/AP

Mourners carry coffins through the streets of Tehran, Iran, on July 7, 1988, during a mass funeral for victims of a downed Iran Air flight. The U.S. Navy shot down the civilian plane in the Persian Gulf, killing all 290 onboard, after mistaking it for an Iranian warplane. AP hide caption

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A Sukhoi Su-25 single-seat, twin-engine jet aircraft with Russian markings. A similar Ukrainian jet was reportedly shot down late Wednesday. Syritsa Mikhail/ITAR-TASS/Landov hide caption

itoggle caption Syritsa Mikhail/ITAR-TASS/Landov

A woman cries near her burning house after shelling in the city of Slovyansk, Donetsk Region, eastern Ukraine, last month. The city of 100,000 has now been retaken from pro-Russian separatists. Dmitry Lovetsky/AP hide caption

itoggle caption Dmitry Lovetsky/AP

Russia's President Vladimir Putin speaks during a session of the St. Petersburg International Economic Forum 2014 in St. Petersburg on Friday. He told the audience that he would respect Sunday's presidential vote in Ukraine. Sergei Karpukhin/Reuters/Landov hide caption

itoggle caption Sergei Karpukhin/Reuters/Landov

A Ukrainian nationalist carries a portrait of Stepan Bandera, founder of a Ukrainian rebel army that fought the Soviet Union in the 1930s and '40s. The rally was held on Jan. 1, 2013. While many Ukrainians see Bandera as a hero, many Russians view him as an ally of Hitler and a mass murderer. Efrem Lukatsky/AP hide caption

itoggle caption Efrem Lukatsky/AP

Workers of the Ukrainian company Metinvest clear away debris in a government building in the eastern Ukrainian city of Mariupol on Friday. Local patrols by steelworkers have forced pro-Russia separatists to retreat from the government buildings they occupied. Evgeniy Maloletka/AP hide caption

itoggle caption Evgeniy Maloletka/AP