Iraqi men hold portraits of Iran's late leader Ayatollah Ruhollah Khomeini (C), Supreme Leader Ayatollah Ali Khamenei (R) and Iraq's late Shi'ite cleric Mohammed Baqir al-Sadr (L) during a demonstration to show support for Yemen's Shi'ite Houthis and in protest of an air campaign in Yemen by a Saudi-led coalition, in Baghdad March 31, 2015. Saudi troops clashed with Yemeni Houthi fighters on Tuesday in the heaviest exchange of cross-border fire since the start of a Saudi-led air offensive last week, while Yemen's foreign minister called for a rapid Arab intervention on the ground. REUTERS/Thaier Al-Sudani