An airstrike blamed on the Saudi-led coalition fighting Shiite rebels in Yemen hit a bus in a busy market on Thursday in the country's north, killing at least 20 people, including children, Yemeni tribal leaders said.
"We call on the Saudi-led coalition to conduct a thorough and transparent investigation into the incident", she said.
"Targeting Saudis and residents in Saudi is a red line", coalition spokesman Turki al-Malki later told Al Arabiya TV.
Well Mark... The International Committee of the Red Cross said the children were on a field trip when their bus was struck at a market in Dahyan, in the northern province of Saada.
He added that Guterres has urged an "independent and prompt" probe into the attack that killed at least 50 civilians, mainly children, and wounded 77 others at a market in Yemen's northwestern province of Sa'ada. He asserted that it evinces a "blatant disregard for rules of war when [a] bus carrying innocent school children is fair game for attack".
After the strike, the United States, which largely supports the coalition's campaign, issued a statement.
The strike was carried out by the Saudi Arabian-led coalition, which is backed in this war by the U.S.
The ICRC stressed that "under worldwide humanitarian law, civilians must be protected during conflict", while the secretary-general of the Norwegian Refugee Council Jan Egeland called it a "grotesque, shameful" attack that showed "blatant disregard for rules of war".
Saudi Arabia, the UAE and their allies in the Arab Coalition intervened in the conflict at the request of Mr Hadi's government.
The world has forgotten Yemen's bloody war, but when you look at these young victims - their tiny bodies, some still struggling for life - you won't be able to forget them.
Footage from the Houthi media office showed a boy wearing a blue backpack with a UNICEF logo being carried into a hospital emergency room with blood pouring down his face and over his traditional Yemeni thawb, an ankle-length garment.
He continued: "The interception resulted in projection of fragments throughout some residential areas, which caused the martyrdom of a Yemeni resident, and injuries to 11 civilians". Iran has used Houthi rebels in the nation to wage a proxy war against its regional nemesis Saudi Arabia. "Causalities from today's attack continue to arrive", the Red Cross stated on August 9.
It accused the Houthis of using children as human shields and said the strikes were carried out in accordance with global humanitarian law.
The missile was sacked from Amran province in northern Yemen on Wednesday night, the coalition said in a statement published by the Saudi Press Agency.
The ballistic missile was sacked from the northern Yemeni province of Amran towards the southern Saudi city of Jizan, said a coalition statement published by the official Saudi Press Agency.
Maliki said those responsible for firing ballistic missiles and targeting civilians would "get what they deserve".
The coalition denied responsibility for those attacks.
Worldwide aid groups were quick to condemn the air strike.