Nepal earthquake: Countries send supplies and rescue teams
27 April 2015 Last updated at 04:40 BST
At least 3,218 people are now known to have died in a massive earthquake which hit Nepal on Saturday.
The UN children's agency Unicef says almost a million children living in affected areas are threatened by poor sanitation and a lack of safe water.
The warning comes as countries from around the world are sending rescue teams and vital supplies.
Hundreds of thousands of people have spent the night outdoors in makeshift shelters fearing more aftershocks.
Ben Bland reports.