The rebels, known as Houthis, were supported by army troops when they fought the tribesmen in Bayda province in clashes that began the night earlier. The Houthis lost 16 fighters and the tribesmen 10, the officials said.
Tens of thousands marched in protest against the Houthis Saturday in the cities of Ibb, Taiz, Hodeida, Dhamar and the capital, Sanaa. In Ibb, protesters set a Houthi military vehicle ablaze before the rebels dispersed them.
The officials spoke on condition of anonymity because they were not authorised to release the information otherwise.