North Korean women carry sacks of mud, trying to reenforce a dam to protect precious crops.

Drought and recent flooding that hit the isolated state have devastated annual crop yields.

Government figures suggest production is down by 40 percent.

For a country that struggles to feed its population even in years of good harvest, aid agencies are increasingly concerned.

The United Nations' World Food Programme (WFP) says under-fives are particularly at risk.

SOUNDBITE: WFP COUNTRY DIRECTOR CLAUDIA VONROEHL SAYING (English):

"WFP is looking particularly after mothers and their young babies because they are in a moment of their life when they really need a special nutrition booster and we see this as our humanitarian task to help them at this very special moment in their life."

The World Food Programme says it's reaching two million children and their mothers in North Korea.

But with many mouths to feed, they warn it's just a stop gap.

An assessment conducted later this month is expected to find large numbers of malnourished children.