A suicide bomber has killed at least 33 people in central Yemen when he blew himself up at a celebration by Shiite militia supporters, medics said.
Dozens of people were also wounded in the attack in the mainly Sunni but Huthi militia-held city of Ibb, the medics said on Tuesday, warning that the death toll was likely to rise.
Among the wounded was Ibb governor Yahya al-Aryani, who was attending the Huthis' commemoration of the Prophet Mohammed's birthday, a medic said.
Security sources said another bomb was discovered at the entrance to the event's venue.
Al-Qaeda in the Arabian Peninsula, the Yemen branch of the jihadist organisation, had pledged to fight the Huthis, who overran the capital Sanaa unopposed in September and have since advanced into other, mainly Sunni districts, including Ibb.
AQAP military chief Qassem al-Rimi vowed in November to carry out fierce attacks against the Shiite militia.
The Huthis, who launched an-off rebellion in the mainly Shiite northern highlands in 2004, have taken advantage of mounting instability to advance far beyond their confessional stronghold.
AQAP leader Nasser al-Wuhayshi has accused the Huthis of collaborating with the United States and Iran to destroy Sunni Muslims.