Houthi fighters gather in the Yemeni city of Aden on Thursday. The Shiite rebels and their allies seized the presidential palace in this southern coastal city. Wael Qubady/AP hide caption

itoggle caption Wael Qubady/AP

Pakistani activists march in support of the Saudi government at a protest in Quetta on March 30, 2015. Pakistan is the latest country to join a Saudi-led coalition fighting Houthi rebels in Yemen. BANARAS KHAN/AFP/Getty Images hide caption

itoggle caption BANARAS KHAN/AFP/Getty Images

Secretary-general of the League of Arab States Nabil Elaraby (left) and Egyptian Foreign Minister Sameh Shukri attend a news conference after the closing session of the Arab League Summit in Sharm el-Sheikh, Egypt, on Sunday. The 22-nation body agreed in principle to establishing a regional security force. Cui Xinyu/Xinhua/Landov hide caption

itoggle caption Cui Xinyu/Xinhua/Landov

Yemenis walk past near oil tankers that were burnt during clashes between Shiite Houthi rebels and their opponents in the capital, Sanaa, in September. Saudi Arabia launched airstrikes this week to counter the Houthis' offensive. Mohammed Huwais/AFP/Getty Images hide caption

itoggle caption Mohammed Huwais/AFP/Getty Images

A Houthi Shiite fighter stands guard Thursday as people search for survivors under the rubble of houses destroyed by Saudi airstrikes near Sanaa Airport in Yemen. Hani Mohammed/AP hide caption

itoggle caption Hani Mohammed/AP

Members of a Saudi women's soccer team, Rana Al Khateeb (left) and captain Rawh Abdullah, practice at a secret location in the capital Riyadh in 2012. Saudi women have had only rare opportunities to play sports. The country sent women to the Olympics for the first time in 2012 and now girls will be allowed to take physical education classes at public schools. Hassan Ammar/AP hide caption

itoggle caption Hassan Ammar/AP

These pop-up targets are part of an advanced drill, named "friend or foe," that tests shooter reaction times. Some targets have a camera, and others, like these pictured, have a gun. The shooter must decide within seconds whether to shoot. Deborah Amos/NPR hide caption

itoggle caption Deborah Amos/NPR

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

Saudi Arabia's King Salman, who assumed the throne on Friday, is shown at the G20 conference in Brisbane, Australia, on Nov. 15, 2014, when he was the crown prince. His succession went smoothly, but the new monarch faces a region in turmoil. Pablo Martinez Monsivais/AP hide caption

itoggle caption Pablo Martinez Monsivais/AP

Venezuelan President Nicolas Maduro is welcomed by Saudi Crown Prince Salman in Riyadh on Sunday. The meeting was part of Maduro's diplomatic tour of OPEC members to discuss falling oil prices, which have hit Venezuela's economy hard. Reuters /Landov hide caption

itoggle caption Reuters /Landov