Followers of the Shi'ite Houthi movement sleep in a makeshift tent camp on main road leading to the airport in Sanaa September 8, 2014. Protesters from the Shi'ite Muslim group the Houthis cut off the road between the capital and Yemen's main airport while warplanes bombed Houthi rebel positions in the north on Sunday in a sharp escalation of weeks of tensions with the government. Tens of thousands of Houthis have spent weeks camping around Sanaa in protest at the government against which they have fought, on and off, for a decade in northwest Yemen. REUTERS/Khaled Abdullah (YEMEN - Tags: POLITICS CIVIL UNREST)