More than 700,000 people have fled their homes in Sudan to escape from fighting between rival military factions, the International Organization for Migration said on Tuesday.
It was not immediately clear if they were heading to Sudan's seven international borders, over which at least 150,000 people have crossed, according to data from the U.N. refugee agency.
IOM spokesperson Paul Dillon told a press conference in Geneva that more than 700,000 people were now displaced within Sudan since fighting began. Last week, the U.N. agency said about 340,000 people were internally displaced.
"It's very difficult right now (for them) to find money. The ATMs aren't working and the banking system is not functioning. Fuel is difficult to come by and expensive," Dillon added.
At the same briefing, the World Health Organization said 604 people had been killed and more than 5,000 injured since the violence erupted on April 15 between the rival factions.
The battles between the Sudanese army and the paramilitary Rapid Support Forces that erupted in the capital Khartoum in mid-April have now engulfed large parts of Sudan, killing hundreds, wounding thousands and unleashing a humanitarian disaster that could not have come at a worse time.
Africa was already facing a deepening set of crises – from drought to floods and a growing list of armed conflicts – that has seen demand surge for life-saving humanitarian assistance.
Now, according to an internal U.N. estimate, 5 million additional people in Sudan will require emergency assistance, half of them children.
By October, some 860,000 people are expected to flee to neighbouring countries including Chad, placing additional strain on nations already facing some of the world's most under-funded humanitarian crises. (For a FACTBOX please click)
Yet a Reuters analysis of United Nations funding data for Africa shows financial support from key donor governments is dropping off.
Securing additional money is a long shot, 12 aid workers, diplomats and donor government officials told Reuters. More likely, they said, funding gaps will grow as Europe focuses on Ukraine, post-Brexit Britain turns inward, and some lawmakers in the United States, the world's largest donor, target budget cuts.
"There is going to be less funding this year," the World Food Programme's (WFP) new executive director, Cindy McCain, told Reuters during a visit to Somalia this month. "I pray that there won't be. But the reality of it is that there is going to be less."
Every day, hundreds of Sudanese trek across the desert scrubland and dry riverbeds that make up large sections of the country's 1,400-km (870-mile) border with Chad. Some 30,000 have arrived so far, according to the U.N. refugee agency UNHCR, which expects it will need to establish five new camps to accommodate them.
Aid agencies are rushing to distribute emergency food and register new arrivals, but resources are tight. 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.