Yemen's conflict is driving an already impoverished country towards humanitarian disaster, displacing tens of thousands of families and exposing many more to the threat of disease and malnutrition, the United Nations children's agency UNICEF said on Monday.
The Arabian peninsula's poorest state has endured years of unrest, but nearly two weeks of war between rebel Houthi fighters and pro-government forces - backed by a Saudi-led campaign of air strikes - has put millions of people in danger.
UNICEF's Yemen representative Julien Harneis said "many, many children" had been killed in the fighting. Hospitals have been shelled and schools taken over by combatants. Fuel shortages threaten to disrupt child immunisation programmes - which need vaccines to be kept refrigerated - and government cash handouts to the poorest third of the population have been suspended.
At the same time the cost of water has risen, as generators pumping the water become more expensive to run, and prices of increasingly scarce food have gone up as people's incomes fall.
The huge displacement of people, with families fleeing the worst-hit cities, also means deteriorating hygiene and sanitation conditions and possible spread of disease.
"We are rushing to a humanitarian disaster," Harneis told Reuters.
UNICEF and the International Committee of the Red Cross are both trying to fly aid shipments into Yemen on Tuesday to start addressing the dire conditions, but say they have struggled to get approval from the Saudi-led coalition and to find planes which will fly into the conflict zone.
"Our main focus is going to be water and sanitation, and medical (aid)," Harneis said by telephone from Jordan.
UNICEF said at least 62 children were killed in the last week of March in Yemen. Harneis said the figure was likely now to be "much, much worse".
In part that may be because of the large proportion of children fighting in the ranks of Yemen's many armed factions.
Harneis said child recruitment was widespread. "All of those more tribal type groups ... up to a third of them are children."
On Thursday, the United Nations put the overall death toll from two weeks of fighting in Yemen at more than 500. Scores more have died since then, including 60 people killed on Sunday in fighting for the port district of Mualla in the southern city of Aden, residents and eyewitnesses told Reuters.
Central Aden has endured some of the worst of the conflict, with residents complaining that water and electricity have been cut off in some neighbourhoods for days.
A Reuters correspondent in the city saw a refuse truck on Monday ferrying around 10 corpses, piled on top of each other, towards one of the city's hospitals.
In the Houthi-controlled capital, Sanaa, residents have also been caught up in the fighting. A local rights group said 29 civilians were killed in an air strike near the airport on the first day of the Saudi-led campaign.
In the longer term, the fighting threatens to reverse steps in health and education which Yemen made despite political turmoil since 2011 street protests, inspired by the broader Arab uprisings, and tribal and provincial unrest.
"We're expecting a real peak in malnutrition," Harneis said.
Yemen is just one of a handful of Arab countries including Syria, Iraq and Libya which show many signs of failed statehood, as armed insurgencies erode central authority. But even before the latest conflict, it was more fragile than others.
"It doesn't have the oil resources of Iraq. It didn't have the infrastructure of Syria. So it's already a very vulnerable society," Harneis said. "On top of this you are adding a layer of intense conflict in the south and bombardment and destruction of the infrastructure in the north."