Army soldiers man a checkpoint outside Amran city, the capital of Amran province, north of Sanaa, amid tension with militants of the Shi'ite Houthi group, April 13, 2014. Fighters loyal to the Shi'ite tribe, who have repeatedly fought government forces since 2004, are trying to tighten their grip on the north as Yemen moves towards a federal system that gives more power to regional authorities. REUTERS/Khaled Abdullah (YEMEN - Tags: POLITICS CIVIL UNREST MILITARY)