At least 20 Shia rebels have been killed and six soldiers wounded in clashes with the Yemeni army in northern Saada, according to officials.
The fighting in the Haydan district of Dafaa on Sunday followed an army offensive to recapture a military camp which has been under Shia rebels' control for the past three months, officials said.
Abdel Malak al-Hawthi, a rebel leader, told news agencies that tribal chiefs have stepped in to mediate a new ceasefire, but warned that his group would escalate fighting "if the government insists on the option of war".
The renewed violence comes despite efforts to implement a peace deal between the government and the fighters, brokered by Qatar.
Thousand of people have been killed since a 2004 uprising in Saada by members of the Zaidi community, a branch of Shia Islam.
The fighters, known as Huthis after Hussein Badr Eddin al-Huthi, their former commander who was killed by the Yemeni army in September 2004, have been battling to restore the Zaidi imamate which was overthrown in a coup in 1962.
Tribal leaders in the northern region of Yemen, a predominantly Sunni country, say more than 30,000 residents have been displaced by the fighting.