At least 40 people have been killed in more than 24 hours of Saudi-led coalition air strikes and fighting in Yemen's central province of Baida, military sources say.
The fighting and air raids in Mukayris, a town seen as a gateway to southern provinces recently recaptured by pro-government forces, left 19 rebels, 15 loyalists and six civilians dead, the sources told AFP.
Coalition strikes against rebel positions in Baida continued on Tuesday (local time) as the fighting raged, they added.
Baida is home to mainly Sunni tribes that have been fighting Shiite Huthi rebels who advanced from their northern stronghold last year.
Mukayris is on the border between Baida and the southern province of Abyan, which loyalists have recaptured along with Aden, Lahj, Daleh and Shabwa since mid-July.
Other clashes were continuing Tuesday, and coalition raids targeted rebels in the vast oil-rich Marib province in the east, witnesses said.
A local Huthi military chief was killed along with several rebels in a coalition raid on one of their positions in Marib, witnesses said.
AFP could not confirm this from rebel sources who rarely acknowledge their losses.
Overnight fighting between Huthis and tribesmen on the border between Sanaa and Marib provinces killed 13 people, tribal sources said.
On Monday, one local official said that up to 53 Huthis were killed in coalition air raids on Marib, but there was no independent confirmation of this.
The Huthis have seized large parts of the country including Sanaa, forcing President Abedrabbo Mansour Hadi to flee to the southern port city of Aden and later to Saudi Arabia.
In March, Saudi Arabia launched a coalition that began an air campaign against the insurgents.
The kingdom and the United Arab Emirates have also backed pro-government forces in Yemen with both arms and troops.
Riyadh accuses Iran of arming the Huthis, a charge the Islamic republic denies.