Soldiers from the United Arab Emirates walk past a military vehicle at the airport of Yemen's southern port city of Aden August 12, 2015. Soldiers from the United Arab Emirates, at the head of a Gulf Arab coalition fighting Iran-allied Houthi forces in Yemen, are preparing for a long, tough ground war from their base in the southern port of Aden. Picture taken August 12, 2015. REUTERS/Nasser Awad