The International Committee of the Red Cross says more than 100 people are believed to be dead after the Saudi-led coalition fighting Iran-backed Houti rebels launched an airstrike on a detention center in southwestern Yemen.
A Red Cross official says teams are working to find survivors under the rubble.
The Saudi-led coalition said it hit a facility in Dhamar where drones and missiles were stored and "all precautionary measures were taken to protect civilians."
A rebel spokesman told the Associated Press that 170 captured government fighters were housed in the center.
Local residents, however, told AP that family members who were critical of the Houthis were housed in the center.
More than five years of fighting between the Houthi rebels and the Saudi-led coalition helping the Yemeni government have led to the deaths of thousands of civilians who are already facing severe food shortages and a lack of quality medical care.