A Syrian soldier walks through the hotly contested city of Qusair on May 22. The Syrian army, backed by Lebanon's Hezbollah militia, has been waging a fierce fight with rebels in the key western city for the past two weeks. STR/STR/AFP/Getty Images hide caption

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In this photo provided by Mouaz Moustafa and the Syrian Emergency Task Force, Sen. John McCain, accompanied by Moustafa (right) visits rebels in Syria on Monday. McCain, who slipped into the country for a surprise visit, favors providing arms to rebel forces in Syria. Mouaz Moustafa/AP hide caption

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Russian President Vladimir Putin (right) and British Prime Minister David Cameron met earlier this month. Cameron said then that he was encouraged by Russia's willingness to take part in a peace conference on Syria. Now, Russia is said to be angry about the EU's decision to lift an embargo on arming the Syrian opposition. Alexey Nikoksky /AFP/Getty Images hide caption

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The Ummayyid Mosque in Damascus has been a mosque for around 1,400 years. It sits in the center of a city where many people are struggling to live normal lives amid war. Steve Inskeep/NPR hide caption

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British Foreign Secretary William Hague (left) talks with Belgium's foreign minister, Didier Reynders, during a European Union foreign ministers meeting in Brussels on Monday. Yves Logghe/AP hide caption

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Sen. John McCain, a member of the Senate Armed Services Committee, briefly entered Syria to meet with rebel forces on Monday, according to his spokesman. Allison Shelley/Getty Images hide caption

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Syrians inspect Saturday the rubble of buildings damaged by government airstrikes in Qusair, Syria. The image was provided by Qusair Lens, and was authenticated based on its contents and other AP reporting. ASSOCIATED AP hide caption

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This image provided by the Syrian Revolution against Bashar Assad and released May 2 shows soldiers loyal to Syrian President Bashar Assad standing amid dead bodies at Bayda village, in the mountains outside the coastal city of Banias, Syria. Anonymous/AP hide caption

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Dr. Zaher Sahloul, a Syrian-American physician in Chicago, heads a group of U.S. doctors providing help to those injured in Syria's civil war. Amy Ta/NPR hide caption

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British Prime Minister David Cameron (left) and Russian President Vladimir Putin viewed the Sochi Olympic Park along the Black Sea coast by helicopter Friday. Nikolsky Alexei /ITAR-TASS /Landov hide caption

itoggle caption Nikolsky Alexei /ITAR-TASS /Landov