SANAA, Aug. 10 (Xinhua) -- A Houthi top official welcomed on Friday the call by UN Secretary-General Antonio Guterres for an independent investigation into the Saudi-led airstrikes which killed dozens of children on a bus in Yemen's northern province of Saada.

"We welcome the call of the UN secretary-general and we are ready to cooperate," Mohammed Ali al-Houthi, chief of Houthi Supreme Political Committee, said on his Twitter account.

On Thursday, two Saudi-led airstrikes hit passenger buses in the Dhahyan popular market, killing at least 43 people, mostly pupils under 10, and injuring 64 others, Yahya Shayem, head of Saada health office, told Xinhua.

The attack triggered popular anger across Yemen and drew mass condemnation from international humanitarian agencies.

Guterres condemned the airstrikes and called for an "independent and prompt investigation," his spokesman said.

The International Committee of the Red Cross also condemned the Saudi-led airstrikes, saying "civilians must be protected during conflict under international humanitarian law."

Henrietta Fore, head of the United Nations Children's Fund (UNICEF), expressed his shock at the incident.

"I'm horrified by the reported airstrike on innocent children, some with UNICEF backpacks. Enough is enough," he said.

However, the U.S.-backed Saudi-led coalition said in a statement that what it targeted were "Iran-allied Houthi rebels who fired a ballistic missile on Wednesday at the Saudi commercial city in the border region of Jazan."

In response, Houthi Spokesman Mohammed Abdulsalam mocked the coalition statement as "absolutely ridiculous."

The Thursday's attack was the latest in a series of deadly airstrikes launched by the Saudi-led coalition on Yemen.

The impoverished Arab country has been locked in a civil war since the Houthi rebels overran much of Yemen and seized all northern provinces in late 2014, including the capital Sanaa.

Saudi Arabia is leading an Arab military coalition that intervened in the Yemeni war in 2015 to support the government of exiled President Abd-Rabbu Mansour Hadi.

More than 10,000 Yemenis, mostly civilians, have been killed in the war, with about 3 million others displaced.