UNITED NATIONS - At least 22 children and four women were killed by a Saudi-led coalition air strike while fleeing fighting in Yemen, the UN aid chief said Friday, condemning attacks on civilians.

In addition to that strike on Thursday four other children died in a separate air strike, the UN undersecretary-general for humanitarian affairs Mark Lowcock said. Both were in Al-Durayhimi district, south of the rebel-held city of Hodeida.

“This is the second time in two weeks that an air strike by the Saudi-led coalition has resulted in dozens of civilian casualties,” said Lowcock in a statement.

A coalition attack on a bus in the northern rebel stronghold of Saada on August 9 killed 40 children, prompting UN Secretary-General Antonio Guterres to call for an independent investigation.

Lowcock echoed Guterres’ appeal for “an impartial, independent and prompt investigation” and said “those with influence” over the warring sides must ensure that civilians are protected.

The coalition has announced that it will investigate the August 9 bus attack that drew strong international condemnation, but rights groups insist that any probe should be impartial. The rebel-run Saba news agency said the air strike on Thursday hit a bus and a home but the United Arab Emirates, a key partner in the coalition, blamed the Huthi rebels for the attack.

Al-Durayhimi lies some 20 kilometers (12 miles) south of Hodeida, and has seen two weeks of fighting between the rebels and pro-government forces backed by the UAE. “I had hoped that the outrage that followed the Saada attack in Yemen two weeks ago would be a turning point in the conflict. Yesterday’s reported attacks in Al-Durayhimi, killing 26 children, indicate that it was not,” said Henrietta Fore, the director of the UN children’s agency UNICEF.

Fore urged the warring sides, their foreign backers and the Security Council to “take action and end this conflict once and for all.”

The UN Security Council this month called for a “credible” investigation of the bus attack in Yemen, but did not demand an independent probe.

Three of the five permanent council members - the United States, France and Britain - have supported the coalition in its military campaign although they have expressed growing concern over the heavy toll on civilians. Kuwait, a non-permanent council member, is part of the coalition fighting the Huthi rebels.

Led by Saudi Arabia, the coalition launched its military campaign in Yemen in 2015 to push back the Huthis who still hold the capital Sanaa and return President Abedrabbo Mansour Hadi to power.

The war has left nearly 10,000 people dead and unleashed what the United Nations describes as the world’s worst humanitarian crisis.

Saudi Arabia foils rebels boat attack in Red Sea

The Saudi-led coalition said on Thursday it had foiled a booby-trapped boat attack by Yemen’s Huthis in the Red Sea weeks after the rebels hit a Saudi oil tanker. A statement cited by state-run Al-Ekhbariya news channel did not identify the target of the attack but the rebel-run Saba news agency said the Huthis hit a Saudi military target inside the kingdom’s territorial waters. It gave no further details.

The coalition statement said “the terrorist attack by a booby-trapped boat was launched from the shores of Hodeida,” a city off the strategic Bab Al-Mandeb straits.

The coalition, which has been fighting the Iran-backed Huthi Shiite militias since March 2015, accused the Huthis and the Iranian revolutionary guards of continuing to threaten international navigation routes and world trade.

It also reaffirmed that the protection of the Bab Al-Mandeb waterway is an international responsibility.

Last month, the Huthi rebels hit a giant Saudi oil tanker in the strategic waterway off Yemen coast causing minor damage.

Saudi Arabia, the world’s biggest crude oil supplier, on July 26 halted exports through Bab Al-Mandeb as a result of the attack before resuming the shipments 10 days later.

Bab al-Mandab is a crucial shipping lane between the Arabian Peninsula and the Horn of Africa, linking the Red Sea to the Gulf of Aden.

About 4.8 million barrels of oil and petroleum products pass through the strait every day, according to US government figures.