"WE COMPLETELY PANICKED"
The Yemen Office of the U.N. High Commissioner for Human Rights said 52 detainees were among the dead, adding at least 68 detainees were still missing. The Houthi-controlled health ministry said 60 bodies were pulled from the rubble at the detention centre, which officials said housed 170 prisoners.
In Dhamar's main hospital, empty and bloodstained white bags lay on the floor after workers stacked bodies in the morgue's fridges.
Portraits of Houthi leaders and "martyrs" hung on the hospital walls and over the beds where wounded prisoners were treated.
"They started arriving after 1 a.m. and we completely panicked; Ambulances kept bringing in scores of wounded people," said Majed al-Fadli, an aid worker at Dhamar's hospital.
"Every 10 minutes there was an ambulance."
The Western-backed alliance intervened in Yemen in March 2015 against the Houthis after they ousted the internationally recognized government in the capital, Sanaa, in late 2014.
The movement, which controls most major Yemeni population centres, has stepped up cross-border missile and drone attacks on Saudi Arabia in recent months. The Saudi-led alliance has responded with strikes on Houthi areas.