A Palestinian boy takes part in a military exercises during a military graduation ceremony organized by Hamas movement in the southern Gaza Strip city of Rafah on June 19, 2013. (Xinhua/Khaled Omar)

Palestinian boys take part in a military exercises during a military graduation ceremony organized by Hamas movement in the southern Gaza Strip city of Rafah on June 19, 2013. (Xinhua/Khaled Omar)

A Palestinian boy takes part in a military exercises during a military graduation ceremony organized by Hamas movement in the southern Gaza Strip city of Rafah on June 19, 2013. (Xinhua/Khaled Omar)

Palestinian boys take part in a military exercises during a military graduation ceremony organized by Hamas movement in the southern Gaza Strip city of Rafah on June 19, 2013. (Xinhua/Khaled Omar)