Hundreds of thousands of children in Yemen face life-threatening malnutrition, millions lack access to health care or clean water, and some have been drafted as soldiers in the year-old war, the UN says.
A UNICEF report on Tuesday said all sides had "exponentially increased" the use of child soldiers in the conflict between Houthi forces, allied to Iran, and a Saudi-led coalition supporting Yemen's President Abd-Rabbu Mansour Hadi.
It knew of 848 documented cases, including boys as young as 10.
"On average, at least six children have been killed or injured every day," said the report Childhood on the Brink.
UNICEF has confirmed 934 children directly killed and 1356 injured, but says they are "only a tip of the iceberg".
"Sixty-one per cent of those (children) killed and injured were in (Saudi-led) air strikes across the country," Julien Harneis, UNICEF's Representative in Yemen said.
All sides have violated international law by using indiscriminate and disproportionate force that means "children die unnecessarily and wrongly", he said, citing multiple coalition strikes on outdoor markets.
Basic services and infrastructure are "on the verge of total collapse," with attacks on schools, hospitals and the water and sanitation system.
The UN said last week the warring parties had agreed to a cessation of hostilities from April 10 and peace talks from April 18, after a year of war that has killed more than 6200 people.
Nearly half of Yemen's 22 provinces are on the verge of famine, the UN's World Food Programme said last week.
The report said an estimated 320,000 children risk severe acute malnutrition, which can leave a child vulnerable to deadly respiratory infections, pneumonia and water-borne diseases. But UNICEF is only able to reach 200,000 of them, Harneis said.
Nearly 10 million children need aid to prevent a further deterioration.
UNICEF estimates nearly 10,000 children under 5 years may have died in the past year from preventable diseases, because of lower vaccination rates and declines in treatment.
