War and drought in Somalia are leading to an unprecedented number of people fleeing across the border into Kenya, an aid agency says.

Save the Children is reporting that every day, about 1,300 people - at least 800 of them children - are arriving at the Dadaab refugee camp.

The monthly number of new arrivals has more than doubled in a year, it says.

Aid workers at the camp say the children are exhausted, malnourished and severely dehydrated.

Save the Children says some families are walking for more than a month to reach the camp.

The conflict in Somalia forces many to head for the Kenyan border but a severe drought and the unaffordable cost of food has made the situation worse.

Although made up of three settlements, Dadaab is often referred to as the largest refugee camp in the world.

It is home to well over 350,000 people.

The humanitarian agency Medecins Sans Frontieres says many of the new arrivals are in desperate need of healthcare.

It says almost half of the children arriving there have never had a vaccination.

With the Somali conflict continuing and several more months of drought expected, conditions in the already overcrowded refugee camp are likely to get even worse.

Efforts to decongest the camp and relocate the refugees have so far made little difference.