Security officials and witnesses say the Saudi-led coalition has launched new airstrikes in at least two Yemeni provinces, piercing a humanitarian pause that started at midnight Sunday.

Security officials and field commanders of forces allied with the coalition say 15 of their fighters were killed in two separate coalition airstrikes in the province of Lahj. The accidental strikes against allied forces wounded more than 40 fighters, they say, adding that the death toll is expected to rise.

The deadly strikes happened near the strategic military base of al-Anad, which is held by the rebels and was also hit by coalition planes Monday. The coalition also struck north of the port city of Aden.

All officials spoke on condition of anonymity because they were not authorized to speak to journalists.