Aug. 9 (UPI) -- A Saudi-led coalition airstrike killed dozens of children Thursday when the bombs hit a school bus in northern Yemen, officials said.
The Houthi rebel-run health ministry said at least 50 people were killed, including at least 29 children, and 63 injured, according to CNN. Most were younger than 10 years old, said Johannes Bruwer, head of the International Committee of the Red Cross in Yemen. His organization tweeted an ICRC-backed hospital "received dozens of dead and wounded.
The coalition called the strike a legitimate military action in retaliation to a Houthi ballistic missile attack that targeted Jizan province late Wednesday, Saudi Arabia's official news agency reported.
U.N. Secretary-General António Guterres condemned the airstrike and offered condolences for the families of the victims. He said all parties involved in the Yemen civil war to respect international humanitarian law and called for an independent investigation.
"The secretary-general urgently renews his call for a negotiated political settlement through inclusive intra-Yemeni dialogue as the only way to end the conflict," a statement from the United Nations said. "He urges all parties to de-escalate and to engage constructively in the political process, including consultations scheduled in Geneva in September."
The Saudi coalition, which has U.S. logistic support, has carried out strikes in Yemen to reinstate the internationally recognized presidency of Abdu Rabbo Mansour Hadi, who rebels drove into exile three years ago.
At least 10,000 people have died in the conflict, United Nations statistics show. In June alone, the coalition carried out 258 air raids on Yemen, nearly one-third of which targeted non-military sites.
Yemen, also reeling from a multi-year cholera epidemic that's killed more than 2,300, has the greatest humanitarian crisis in the world, humanitarian agency Cooperative for Assistance and Relief Everywhere said.
"Since , 22.2 million people are now in need of humanitarian assistance, among which 11.3 million are in acute need of immediate assistance to save or sustain life, mostly women and children," the group said.
The special envoy of U.N. Secretary-General for Yemen Martin Griffiths is pushing for peace talks and plans to invite combatants to a first round of negotiation in Switzerland next month.