A photo taken in January 2014 and released by the United Nations Relief and Works Agency for Palestine Refugees (UNRWA), shows residents of the besieged Palestinian camp of Yarmouk, queuing to receive food supplies, in Damascus, Syria. AP hide caption

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Secretary of State John Kerry told CBS News the U.S. is pushing for Syrian President Bashar Assad to seriously discuss a transition strategy to quell the Arab country's four-year civil war. Brian Snyder/AP hide caption

itoggle caption Brian Snyder/AP

Girls carrying school bags provided by UNICEF walk past destroyed buildings on their way home from school on March 7 in the rebel-held al-Shaar neighborhood of Aleppo, Syria. So many people have fled the city and so much of its infrastructure has been destroyed that nighttime satellite images show 97 percent less light there compared with four years ago. Zein al-Rifai/AFP/Getty Images hide caption

itoggle caption Zein al-Rifai/AFP/Getty Images

Dura Europos, a Roman walled city in eastern Syria, dates back to 330 B.C. The main gate is shown here in a photo from 2010. It's one of the many important archaeological sites militants of the self-styled Islamic State have ransacked and damaged. EPA /Deir Ezz-Zour Antiquities Department/Landov hide caption

itoggle caption EPA /Deir Ezz-Zour Antiquities Department/Landov

Syrian volunteers cover mosaics in the Ma'arra museum with a protective layer of glue, covered by cloth. Ma'arra Museum Project/Safeguarding the Heritage of Syria and Iraq Project hide caption

itoggle caption Ma'arra Museum Project/Safeguarding the Heritage of Syria and Iraq Project

Traditional desserts, like these served in 2010 at the original Naranj restaurant in Damascus, offer sweet, familiar flavors at the restaurant's various locations in the Middle East. A platter like this shows up at the end of every meal at Naranj, and all the pastries are made in-house. Jan Smith/Flickr hide caption

itoggle caption Jan Smith/Flickr

Turkish soldiers during the military operation in Syria on Sunday. Turkey launched the raid to evacuate some 40 soldiers guarding the Tomb of Suleyman Shah, grandfather of the founder of the Ottoman Empire. Xinhua/Landov hide caption

itoggle caption Xinhua/Landov

Saudi Arabia's Prince Turki al-Faisal, shown in 2013 in Bahrain, says the 'pinpricks' against the Islamic State have not been effective. The former intelligence chief also says the campaign needs to be better coordinated. Mohammed Al-Shaikh/AFP/Getty hide caption

itoggle caption Mohammed Al-Shaikh/AFP/Getty

Migrants who survived a shipwreck are escorted as they arrive at the Lampedusa harbor on Wednesday. Some 300 others drowned in the latest such disaster triggered by people fleeing conflicts in North Africa. Antonio Parrinello/Reuters/Landov hide caption

itoggle caption Antonio Parrinello/Reuters/Landov

Members of the family of Kayla Mueller, 26, have confirmed that their daughter has died. She had been held captive since being taken prisoner in 2013 while doing humanitarian work in Syria. The Mueller Family hide caption

itoggle caption The Mueller Family

Syria's President Bashar Assad is seen Monday during the filming of an interview with the BBC in Damascus. Assad said third parties including Iraq were conveying information about a U.S.-led campaign of airstrikes against the self-declared Islamic State group in Syria. SANA/Reuters/Landov hide caption

itoggle caption SANA/Reuters/Landov

Members of the family of Kayla Mueller, 26, have confirmed that their daughter has been held captive since being taken prisoner in 2013 while doing humanitarian work in Syria. ISIS claims Mueller died in an airstrike Friday. The Mueller Family hide caption

itoggle caption The Mueller Family