At least six people were killed on Monday in fresh sectarian clashes between armed Shiite and Sunni groups in Yemen's northern province of Saada, a tribal source told Xinhua. The fighting erupted Monday evening after Sunni Muslims were stopped at a checkpoint manned by an armed group affiliated with the Saada-based Shiite sect, also known as Houthi rebels. "The Sunni men were stopped at the checkpoint in Ashash area in Kutaf district and were ordered to surrender their weapons," said Abdullah Manna, a tribal dignitary in Kutaf. "The Sunni group refused and quarrelled with the Shiites that triggered fierce clashes, leaving two Sunni and four Shiite men died," Manna told Xinhua by phone. Several others were also wounded as sectarian tension escalated in nearby villages, he said. Clashes between the Sunni and Shiite groups were frequent in Saada province since the Shiite Houthi rebels stormed a Sunni-held mosque in the area in September last year. The Shiite sect is a majority in Saada province but forms the minority in the whole country. The Houthi group has controlled most parts of Saada after they reached a truce with the central government in Sanaa in early 2010 following a six-year sporadic war against the Yemeni army. After former President Ali Abdullah Saleh stepped down in February 2012 as part of a UN-backed power transfer deal following one-year street protests, the Houthis allied with Saleh's loyalists to fight against the Sunni groups, which are supporting the Muslim Brotherhood, known as Islah Party in Yemen that is the main partner in the current transitional government. The Yemeni government accuses Shiite-dominated Iran of supporting the Houthi rebels, but Tehran always denies such charges.