SANAA, Yemen (AP) -- The Saudi-led coalition fighting Yemen's rebels attacked a detention center in the southwestern province of Dhamar with several airstrikes Sunday, killing at least 60 people and wounding several dozen, officials and the rebels' health ministry said.
The attack was the deadliest so far this year by the coalition, which has faced international criticism for airstrikes that have killed civilians and hit non-military targets.
Yemeni officials said Sunday's strikes targeted a college in the city of Dhamar, which the rebels, known as Houthis, were using as a detention center. The coalition denied it had struck a lockup, saying it had targeted a military site.
"We were sleeping and around midnight, there were maybe three, or four, or six strikes. They were targeting the jail, I really don't know the strike numbers," wounded detainee Nazem Saleh said while on a stretcher in a local hospital. He said the International Committee of the Red Cross had visited the center two times before the airstrike.
Youssef al-Hadhri, a spokesman for the Houthi-run Health Ministry, said at least seven airstrikes hit three buildings in the complex overnight.
The ICRC, which inspects detention centers as part of its global mission, said it had visited the site in the past. Former detainees, meanwhile, said the Houthis had also used the site in the past to store and repair weapons. The Saudi-led coalition said it had hit a military facility used by the rebels to restore drones and missiles.
On Sunday, Sweden's foreign minister was holding talks in Jordan, part of her efforts to relaunch negotiations after years of stalemate between the warring sides. Saudi Arabia intervened on behalf of the internationally recognized government in March 2015, after the Iran-backed Houthis took the capital city. The conflict has claimed tens of thousands of lives, thrust millions to the brink of famine and spawned the world's worst humanitarian crisis.
The rebels' Health Ministry said in a statement at least 60 people were killed in Sunday's airstrikes. Another 50 were wounded. It said rescue workers have been pulling bodies from the site.
The Saudi-led coalition said it had hit a Houthi military facility used as storage for drones and missiles in Dhamar, "in accordance with international humanitarian law."
It said "all precautionary measures were taken to protect civilians."
Col. Turki al-Maliki, a spokesman for the coalition, was quoted by the Saudi-owned Al Arabiya TV as denying the target was a prison.
Mohammed Abdul-Salam, spokesman for the Houthis, posted on his telegram account graphic photos that showed bodies and severed limbs under the rubble.
Abdul-Qader el-Murtaza, a rebel official, said dozens of captured government fighters were being held at the site.
"The targeted prison housed over 170 prisoners of war, most of whom were supposed to be part of a local exchange deal," he was quoted as saying by the Houthi-run al-Masirah TV.
The Red Cross said it sent urgent medical supplies and 200 body bags to Dhamar. Franz Rauchenstein, head of the ICRC delegation in Yemen, said he was headed to Dhamar. "We have visited detainees in this location before," he said, confirming the site's use as a lockup.
Local residents said family members arrested for being critical of the Houthis were imprisoned in the detention center. They said at least seven airstrikes hit the area.
Omat al-Salam al-Haj, a mother of a detainee, said the center housed anti-Houthi political detainees who were rounded up over suspicions of co-operating with the coalition.
Former detainee Mansour al-Zelai said the Houthis were restoring weapons in and close to the detention center.
Houthi rebels have been using scores of lockups including schools, mosques, and houses as detention centers, filling them with thousands of political detainees to use them later in prison-swap deals.
The Associated Press documented that many of these sites were rife with torture and abuses including Dhamar's community college.
Former detainees recalled torture and abuses inside this detention center, which is part of the University of Dhamar, which came under a series of airstrikes before.
Rights groups have also documented before that Houthis place civilian detainees in detention centers as human shields by placing them next to army barracks, under constant threat of airstrikes.
The attack came as the Saudi-led coalition's partners --- chiefly the United Arab Emirates and an array of Yemeni militias --- are increasingly at odds over the war's aims. The past weeks have seen heavy fighting in Yemen's south between government forces and southern secessionist militias armed and funded by the United Arab Emirates. The separatists have taken control of the port city of Aden, which serves as an interim capital since the Houthi takeover of Sanaa in 2014.
On Thursday, Emirati jets bombed convoys of government forces, killing scores in series of airstrikes to prevent them from retaking Aden.
The Emirati strikes sparked popular anger against the UAE. Activists launched an online petition collecting signatures to "kick Emiratis out of Yemen" and members of the Yemeni government issued a statement demanding the president to end the UAE role in Yemen.
On Sunday, Anwar Gargash, UAE Minister of State for Foreign Affairs, in a Twitter post, reminded of the coalition's goal, saying "confront the challenge of the Houthi coup."
Sunday's airstrike is not the first to hit a rebel-run detention center.
In October 2016, an airstrike by the Saudi-led coalition hit a prison complex in the Red Sea port of Hodeida, killing at least 58 people, most of whom were prisoners serving jail terms for minor crimes or who were in pre-trial detention. At the time, the coalition said the prison complex was used as a command center for Houthis.