At least 40 killed in Yemen

At least 40 people have been killed in three days of fighting between Shia Muslim rebels and Sunni tribesmen, sources on both sides said on Sunday, as sectarian fighting that flared up in October in the north drew closer to the capital Sanaa. Fighters loyal to the Shia Houthi tribe, who have repeatedly fought government forces since 2004, are trying to tighten their grip on the north as Yemen - home to one of al Qaeda's most active branches - moves towards a federal system that gives more power to regional authorities.
Gulf Arab states and the United States are particularly concerned about violence in the Western-allied country as it shares a long border with top oil exporter Saudi Arabia and its coast runs alongside Red Sea and Gulf of Aden shipping lanes.