Almost a quarter of a million children are now living in squalid refugee camps in Bangladesh after crossing the border from Myanmar, according to UNICEF.

More than 90,000 of them are believed to be under the age of five and are in conditions where they are vulnerable to the spread of disease.

The United Nations has said Myanmar’s actions against the Rohingya amount to ethnic cleansing.

And aid agencies are struggling to cope. UNICEF spokeswoman Marixie Mercado says the conditions are squalid: “They are living in conditions that are prime for the spread of diseases. They are living pretty much anywhere that they have been able to find space, there is very very little safe water, there are very, very few latrines, there are many mosquitoes.”

Some aid is getting through to the camps but with an estimated 60 percent of all the refugees being childrenhealth is a major concern. On Saturday the Bangladesh government will carry out a U.N. supported vaccination campaign aimed at reaching 100 thousand children.

On Friday protestors in Bangladesh carried a makeshift coffin for Myanmar’s de facto leader, Aung San Suu Kyi as worldwide anger grows at her apparent failure to act.

But the international community is aware that it’s children on whom the focus is most urgently needed.