By Mohammed Ghobari SANAA (Reuters) - At least three people were killed in fighting between rival Muslim clans in northern Yemen on Sunday, a local official said, bringing the death toll from five days of clashes to 58 as the government tried to broker a ceasefire. The battles between Shi'ite Muslim Houthi fighters and rivals from a Sunni Salafi group erupted last Wednesday in the mountainous Saada province, which has long been outside the control of the central Yemeni government. Yemen's stability is a priority for the United States and its Gulf Arab allies because of its strategic position next to oil exporter Saudi Arabia and shipping lanes, and because is home to one of al Qaeda's most active wings. The sectarian fighting in the north has cast a shadow over national reconciliation efforts launched this year after long-serving President Ali Abdullah Saleh was forced to step down following a popular uprising in 2011.