The United Nations children's fund has warned that the Central African Republic is heading for a humanitarian disaster.
UNICEF says children are at risk from overcrowded camps and poor sanitation.
It says measles has broken out at the airport in the capital, Bangui, where about 100,000 people are seeking refuge from clashes between rival militias.
They press right up against the airport runway, hoping that French troops there may provide a measure of safety, the BBC reports.
Almost half of Bangui has fled and there is a threat of cholera and typhoid, but people are still to terrified to go home.
Pressure on president
Reports that the president is to step down have been denied. Officials say that Michel Djotodia's resignation is not on the agenda.
His spokesperson told the BBC that the president was on his way to neighbouring Chad to "attend a regional summit, but not to resign".
Mr Djotodia's failure to quell violence between Christian and Muslim militias has prompted speculation that he may indeed step down at the summit.
"It's finished for him now," a source close to him was quoted as telling Reuters.
A senior diplomatic source in Paris and political sources in Bangui told Reuters that regional leaders led by Chad had run out of patience with Mr Djotodia, who seized power in March last year as the head of Muslim Seleka rebels.