Ukraine's President Petro Poroshenko (R) and Dutch ambassador to Ukraine Kees Klompenhouwer commemorate victims of Malaysia Airlines Flight MH17 outside the Dutch embassy in Kiev on July 21. The downing of the airliner with the loss of nearly 300 lives has sharply escalated the crisis in Ukraine, and may mark a pivotal moment in international efforts to resolve a situation in which separatists in the Russian-speaking east have been fighting government forces since protesters in Kiev forced out a pro-Moscow president and Russia annexed Crimea. Reuters/Valentyn Ogirenko