An air strike at a camp for displaced people and refugees in Houthi-controled northern Yemen on Monday killed 45 people and wounded 65, the International Organization for Migration (IOM) said.
The strike hit the vicinity of the Mazraq refugee camp in northern Yemen, spokesman Joel Millman said, citing IOM staff at the scene. He said it was not immediately clear how many of the casualties were civilians or armed personnel.
Another humanitarian official said earlier that the strike had hit a truck full of Houthi militiamen at the gate to the camp, killing nine residents, two camp guards and an unknown number of fighters.
A Saudi-led coalition was bombing Yemen for a fifth day Monday to try to weaken the Iranian-allied Houthi militia and allied military units.
The air attacks have also targeted their southward advance on the port city of Aden, the last bastion of the Saudi-backed president, Abd-Rabbu Mansour Hadi.
Yemen's foreign minister blamed Iranian-allied Houthi fighters for the airstrike, denying any link to Saudi-led military operations.
Riyadh Yaseen, speaking to reports in Saudia Arabia, said the explosion on the camp was not from Arab coalition forces but by "artillery strikes" by the Houthis.
Saudi officials were not immediately available for comment.
Mazraq, in the province of Hajja next to the Saudi border, is a cluster of camps home to thousands of Yemenis displaced by over a decade of wars between the Houthis and the Yemeni state, as well as East African migrants.
Over the last five days of Saudi-led bombing, around 750 families have been displaced to the camps from the Houthi heartland region of Saada in the far north. Another air strike in the vicinity on Saturday killed several soldiers, the official added.