A source from Marib State Hospital, who asked not to be named due to restrictions to speaking to media, told most of the dead were soldiers targeted by mortars while taking rest.
According to the information obtained by a military source, an armed unmanned aerial vehicle was used in the attack.
The Yemeni government or the Houthis have yet to issue a statement on the attack.
At least 23 Houthis rebel and three Yemeni army soldiers were killed Saturday in clashes in the capital, Sanaa.
According to information from Yemeni security sources, the Yemeni army carried out preemptive action against Houthi rebels preparing to attack military points in Nihm district.
The army announced it repulsed Houthis attacks in the Al-Bayda province.
The crisis escalated in 2015 when a Saudi-led military coalition launched a devastating air campaign aimed at rolling back Houthi territorial gains.