In addition, three more people were killed and six injured when strikes hit three vehicles in Al Hali District in Hudaida province, the UN's Office for the Coordination of Humanitarian Affairs said in a statement Thursday.
A Saudi-led coalition air strike at a fruit-and-vegetable market near Yemen's flashpoint Red Sea port of Hudaida killed at least 21 civilians, including children, the UN humanitarian aid agency said Thursday.
Wednesday's attack came amid mounting fears of a fresh coalition assault on Hudaida — a city that has been the lifeline for international aid deliveries to Yemen, a country ravaged by a brutal three-and-a-half-year war between the Saudi-led alliance and Iran-backed rebels known as Houthis.
The coalition has been trying to wrest Hudaida from the Houthis but the campaign, like the rest of Yemen's war, had fallen into a stalemate.
The air strike, which hit a vegetable packaging facility in the outdoor market in the town of Bayt el Faqih, just south of Hudaida, also wounded 10 people. Initial reports had five dead but the death toll steadily climbed overnight.
The director of the Bayt el Faqih hospital, Abdullah Shahawi, said all the victims were civilians and that at least two children were among the dead.
In the capital Saana, the Houthi-run Al Masirah TV reported a lower casualty figure, saying at least 20 people died and 10 were wounded. The different death tolls could not immediately be resolved.
Also on Wednesday, three more people were killed and six injured when strikes hit three vehicles on July 7 road in Al Hali District in Hudaida province, the UN's Office for the Coordination of Humanitarian Affairs said in a statement Thursday.
"Civilians are paying a shocking price because of this conflict," said UN Humanitarian Coordinator for Yemen Lise Grande. "This is the third time this month that fighting has caused mass casualties in Hudaida."
Video footage obtained by The Associated Press showed the aftermath of the strike, with body parts lying scattered across the market and coffins lined up in the hospital. The video could not be independently confirmed but it corresponded to events reported by the AP.
A spokesman for the Saudi-led coalition did not respond to multiple phone calls and messages seeking comment.
Inflation pushing famine
Journalists have been barred from visiting rebel-held areas in Hudaida, including where Wednesday's air strike took place. Yemeni security officials confirmed the strike but didn't know what the intended target was.
It's not uncommon for coalition jets to hit civilians and wedding parties, funerals, residential homes and hospitals have been bombed in the past. In August, an air strike hit a bus carrying children on their way to school in northern Yemen, killing more than 40.
The growing number of civilian casualties in the war has prompted right groups to call for the suspension of the multibillion-dollar US and European arms sales to Saudi Arabia, for decades among the world's largest buyers of weapons.
Save the Children said Thursday the cost of basic food items such as flour, rice, salt, sugar and cooking oil has nearly doubled since the conflict erupted in March 2015.
The average income in Yemen has more than halved, meanwhile, falling to just $3.39 a day. The organisation also said that 52 percent of the population lives under the international poverty line — up from 30 percent in 2014.
"The economic collapse is Yemen's silent killer; many Yemenis are struggling just to survive," said Tamer Kirolos, the group's Yemen director.
Saudi Arabia and its powerful young Crown Prince Mohammed bin Salman, who has been leading the coalition campaign in Yemen, have been facing international outrage over the killing of journalist Jamal Khashoggi earlier this month inside the Saudi Consulate in Turkey. Khashoggi's slaying has also sparked widespread condemnation of the crown prince and marred his international standing after Turkish reports alleged that a member of his entourage was involved in the killing.
Crippling Yemen via Hudaida
The Saudi-led coalition recently sent reinforcements to Yemen's west coast for what many fear would be an intensified battle for Hudaida.
The city's port literally keeps millions of starving Yemenis alive, as it serves as an entry point for 70 percent of food imports and international aid. A protracted siege of Hudaida by the coalition could cut off that lifeline.
Yemeni officials said Wednesday that reinforcements had arrived in tanks and armoured vehicles provided by the United Arab Emirates, a key coalition member. All officials spoke on condition of anonymity because they were not authorised to talk to reporters.
The assault to retake Hudaida first began in June, then paused in August as the UN envoy for Yemen tried to cobble together peace talks, the first in two years. That attempt fell apart, and the offensive resumed in mid-September.
Hudaida fighting has already killed hundreds of civilians and forced hundreds of thousands to flee their homes.
Citing humanitarian partners, the UN humanitarian aid agency said more than 170 people were killed, at least 1,700 were injured and more than 570,000 people have been forced to flee their homes across Hodeida province since fighting escalated in June.
An estimated 10,000 people have been killed so far and the conflict has devastated Yemen and pushed it to the brink of famine. The war has also left around two-thirds of Yemen's population of 27 million relying on aid, and over 8 million at risk of starvation.