The rebels, known as Houthis, say the early Monday strike hit the Sawan neighborhood in eastern Sanaa.
Smoke billowed from the slum area, which lies hundreds of meters (yards) from a military camp used by the rebels.
Airstrikes and ground fighting in Yemen have continued for the third day despite a U.N.-brokered truce between the rebels and the internationally-backed government in exile and its allies.
Hospital officials say women and children were among the casualties. The officials spoke on condition of anonymity because they are not authorized to talk to reporters.
More than 3,000 people have been killed in Yemen since the airstrikes began in March.