Dozens of others were wounded in the strike in the central province of Marib on Saturday, officials say.
The camp, about 170km (105 miles) east of the capital, Sanaa, targeted a mosque as people gathered for prayer, military sources told Reuters.
Yemen’s government has blamed Houthi rebels for the attack, but there has been no claim of responsibility.
Officials said they expected the death toll to rise.
Yemeni President Abdrabbuh Mansour Hadi condemned the “cowardly” attack in a statement carried by Saba, a state news agency.
The attack “confirms without doubt that the Houthis have no desire for peace”, Mr Hadi was quoted as saying.
In August last year, Houthi rebels launched a missile attack on a Yemen government forces military parade in the southern port city of Aden, killing at least 32 people.
Yemen has been devastated by a conflict that escalated in March 2015, when Houthi rebels seized control of much of the west of the country and forced President Hadi to flee abroad.