There has been a sharp increase in the number of people fleeing from Sudan to Chad to escape fighting and dire conditions, and aid funding is failing to keep up with needs, the United Nations refugee agency said on Friday.

More than 400 people a day have been crossing into eastern Chad over the past week, a 20-fold increase from the numbers seen in recent months, UNHCR said.

They were fleeing Sudan's Darfur, Kordofan and Blue Nile regions — which have all been hit by clashes between Sudan's army and the paramilitary Rapid Support Forces in a more than three-year-old civil war.    

There were "people who tell us that they flee the conflict, they flee the aerial bombardments, they flee the drone attacks," Mamadou Dian Balde, UN Regional Refugee Coordinator for the Sudan Situation, told reporters in Geneva via video link from Nairobi. 

Only 18% of the $1.6-billion funding it needed this year had come in, UNHCR said.    

“It means less food. It means less capacity for people to be relocated to safer areas. It means less capacity to shelter themselves,” Dian Balde said.

The agency warned of potential knock-on effects if Sudanese refugees’ basic needs are not met in Chad, saying its analysis shows many move on towards Europe after repeated failed attempts to find safety.

The civil war has devastated wide swathes of Sudan, displacing up to 14-million people, ruining harvests and decimating the economy, according to UN estimates.

Drought and other harsh conditions were also forcing people to move, UNHCR said.

Almost 1-million refugees have crossed into Chad since the conflict began, more than 55 000 so far this year, according to UNHCR data. 

Aid groups like UNHCR face major funding shortfalls after the administration of US President Donald Trump and other donor countries cut billions of dollars in foreign assistance over the past year.