Now, according to an internal U.N. estimate obtained by Reuters, 5 million additional people in Sudan will require emergency assistance, half of them children.
Even before the latest crisis, U.N. humanitarian appeals for Africa faced a $17-billion funding gap this year, risking leaving millions without lifesaving assistance.
Last year, it spent a third of its overseas aid budget housing refugees inside the UK, a British aid watchdog said in March.
Sudan was hosting over 1 million refugees, mainly from South Sudan, Eritrea, Ethiopia and Syria, before the outbreak of fighting last month.
Aid workers have been killed, food aid looted, and WFP says it's running out of stocks.