Saudi-led air strikes on a school in a rebel-held province of Yemen have killed 10 children, aid agencies said on Sunday, prompting fresh concerns over civilian casualties in the 17-month war.
Another 28 children were wounded in the raids which occurred on Saturday in the town of Haydan, in Saada province, said the Paris-based Doctors Without Borders (MSF). The United Nations confirmed the attacks.
A Saudi-led coalition of Arab states has been battling the Iran-backed rebels since March 2015 when the insurgents seized the capital Sanaa before expanding to other parts of the country.
Only 10 days ago, it acknowledged "shortcomings" in two out of eight cases it has investigated of strikes on civilian targets in Yemen that have been condemned by the United Nations.
Doctors Without Borders "received 10 dead children and 28 wounded, all under the age of 15, who are victims of air strikes on a Qur'anic school in Haydan," said spokeswoman Malak Shaher.
They were admitted to a field hospital near the school before being transferred to a public hospital, she told AFP.
"We demand from all parties to take the measures necessary to protect civilians," Shaher said.
The United Nation's children agency, UNICEF, also reported the attack.
It warned that "with the intensification in violence across the country in the past week, the number of children killed and injured by air strikes, street fighting and landmines has grown sharply."
The Shia rebels posted pictures and videos on Facebook of dead and bloodied children wrapped in blankets.
'Heinous crime' 
Huthi spokesman Mohammed Abdulsalam said warplanes "targeted" children at the Jomaa bin Fadhel school, in what he described as a "heinous crime".
The Saudi Press Agency said coalition warplanes struck a Houthi "training centre" on Saturday in Saada, killing several insurgents, including a leader it identified as Yehya Munassar Abu Rabua.
The Arab coalition launched its air war against the Houthis on March 26, 2015.
After a three-month pause, it resumed the air strikes on Tuesday, less than 72 hours after UN envoy Ismail Ould Cheikh Ahmed announced the collapse of peace talks in Kuwait.
Raids struck a food factory in Yemen's rebel-controlled capital, killing 14 people, according to medics.
The factory is near a military equipment maintenance centre targeted by the coalition.
The United Nations had also voiced concern over the increased fighting in Yemen during the past week, warning of its humanitarian consequences with more than 80% of the population needing aid.
"UNICEF calls on all parties to the conflict in Yemen to respect and abide by their obligations under international law," the agency said in its latest statement.
"This includes the obligation to only target combatants and limit harm to civilians and civilian infrastructure."
Blacklisted 
Saudi Arabia reacted angrily to a decision in June to blacklist the coalition after a UN report found the Arab alliance responsible for 60% of the 785 deaths of children in Yemen last year.
UN Secretary General Ban Ki-moon had accused Saudi Arabia of threatening to cut off funding to United Nations aid programmes over the blacklist, a charge denied by Riyadh.
Coalition members -- Bahrain, Kuwait, Qatar, Saudi Arabia and the United Arab Emirates -- as well as Yemen have formed a 14-member investigative team which has probed claims of attacks on a residential area, hospitals, markets, a wedding and World Food Programme aid trucks.
It found the coalition guilty of "mistakenly" hitting a residential compound after receiving "imprecise" intelligence information and offered compensation to families of the victims.
The team also held the coalition responsible for air strikes on an MSF-run hospital, also in Haydan, but accused the rebels of having used the hospital as a hideout.
The UN says more than 6,400 people, mostly civilians, have been killed in Yemen since the coalition air campaign began in March last year.
The coalition meanwhile announced that Saudi air defences on Saturday intercepted a Scud missile fired from Yemen towards the kingdom.
Coalition jets struck the source of fire in an area between Saada and Amran province, near the capital.
Around 100 members of the Saudi forces and civilians have been killed inside the kingdom's borders since the coalition campaign began.