Yemeni security officials say Saudi-led airstrikes and clashes have killed some 40 Shiite rebels and their allies over the past 24 hours.

The officials, who are neutral in a conflict that has split the security forces, say the airstrikes and fighting took place mostly in Ibb province into Monday, and near the cities of Mocha and Taiz. The raids in Taiz also killed four civilians.

Anti-rebel fighters say 13 of their own forces were killed and more than 20 wounded in the Taiz fighting.

All officials spoke on condition of anonymity because they weren't authorized to brief reporters.

Yemen's fighting pits the rebels, known as Houthis, and allied army units against forces loyal to the internationally recognized government, as well as southern separatists and militants.