The United Nations says Sudan has refused to allow a top United Nations official to fly over the Darfur region on his way to Chad.
U.N. emergency relief coordinator Jan Egeland was planning to go to eastern Chad to visit Sudanese refugee camps.
Mr. Egeland's spokeswoman told VOA Tuesday that the decision makes it impossible for him to continue his planned five-day trip to the region. She said he instead will fly to Paris to attend meetings of the Organization for Economic Cooperation and Development.
On Monday, the Sudanese government barred Egeland from visiting the war-torn Darfur region and Sudan's capital, Khartoum.
Sudan's official news agency says Egeland's visit has been postponed for 10 days, because of what it called the government's desire to make the visit successful.
Mr. Egeland said he believes the Sudanese government does not want him to see how bad the situation in Darfur has become.
Mr. Egeland spokeswoman noted that the Sudanese government had issued him a visa for the visit that was set for this week.
Three years of fighting between rebels, government forces and Khartoum-backed militias in Darfur has killed an estimated 180,000 people and left another two million homeless.
Egeland is in charge of U.N. humanitarian relief for the displaced. He said Sudan's latest move reflects the decline in U.N.-Sudanese relations over the proposed deployment of U.N. peacekeepers to Darfur.
Some information for this report was provided by Reuters.