The IOM has received just 21% of the support it needs to provide crucial aid to the Sudanese, already plagued by conflict and now facing hunger, disease and floods, Mohamed Refaat, who leads the IOM's Sudan mission, told a briefing.
"The international community is not doing enough," Refaat said.
"Without an immediate massive and coordinated global response, we risk witnessing tens of thousands of preventable deaths in the coming months," he added.
Some one in five people have been displaced in Sudan, with 10.7 million people internally displaced and 2.3 million having fled across borders, according to the IOM.
A conflict in Sudan that erupted in April 2023 has unleashed waves of ethnic violence and created famine-like conditions across the country.
