UN Secretary-General Antonio Guterres is sending an envoy to the Sudan region amid the "unprecedented" situation there, as deadly hostilities enter a third week, his spokesman said Sunday.
The announcement came as the army and heavily armed paramilitaries in Khartoum continued fighting, even as a widely breached ceasefire was extended for 72 hours.
UN emergency relief coordinator Martin Griffiths, who will serve as the envoy, said in a separate statement Sunday that Sudan's "humanitarian situation is reaching breaking point".
"I am on my way to the region to explore how we can bring immediate relief to the millions of people whose lives have turned upside down overnight," he said.
However, massive looting of humanitarian offices and warehouses had "depleted most of our supplies. We are exploring urgent ways to bring in and distribute additional supplies," he said.
The "obvious solution," he added, would be to "stop the fighting".
More than 500 people have been killed and tens of thousands of people forced to leave their homes for safer locations within the country or abroad since battles erupted on April 15.
"In light of the rapidly deteriorating humanitarian crisis in Sudan," spokesman Stephane Dujarric said in a statement announcing Griffiths' deployment, the envoy would travel "to the region immediately".
"The scale and speed of what is unfolding is unprecedented in Sudan," his statement said. "We are extremely concerned."
Griffiths said that families were struggling to access water, food, fuel and other commodities, with some unable to relocate due to the cost of transportation out of the worst-hit areas.
Urgent health care, he said "is severely constrained, raising the risk of preventable death".
Five containers of intravenous fluids and other emergency supplies were docked in Port Sudan awaiting clearance by authorities, he added.
For its part, the United Nations' World Food Programme said on Monday it will immediately lift the suspension of its operations in Sudan that was put in place after the deaths of its team members.
"WFP is rapidly resuming our programs to provide the life-saving assistance that many so desperately need right now," WFP executive director Cindy McCain wrote on Twitter.
The WFP said on April 16 it had temporarily halted all operations in Sudan after three of its employees were killed in clashes between the Sudanese army and the paramilitary Rapid Support Forces (RSF) a day earlier.
(FRANCE 24 with AFP and Reuters)