The UN said that Jan Egeland, the UN's humanitarian relief coordinator, was to have started a visit to Darfur to inspect the dire situation facing people there after three years of war. He was then to go to the capital Khartoum and to a refugee camp in neighbouring Chad.
However Mr Egeland said Sudanese authorities told him he could not go for security reasons and because of the controversy over the appearance of contentious cartoons of the Prophet Mohammed in European newspapers.
"The governors of South Darfur, West Darfur and North Darfur said I could not travel there because they feared for my security," he told AFP from the southern Sudanese town of Rumbek from where he was to have travelled to Darfur.
"The Sudanese had a problem with my Norwegian nationality because of the Danish cartoons," Mr Egeland said, noting that similar reasoning had been used last month to deny access to Darfur by a senior Swedish official.
He dismissed Khartoum's explanations claiming the real reason behind the prohibition was Sudan's opposition to his increasingly critical statements about the situation in Darfur and his calls for the deployment of UN peacekeepers there.
"I believe the government does not want me to see what is going on Darfur," Mr Egeland said. "I wanted to go to a place where tens of thousands of people were displaced.”
Mr Egeland also accused Khartoum and its proxy militia, the Janjaweed, of attacking aid workers and obstructing relief supplies to the desperately needy civilian population.
"The Janjaweed and the government are harassing us, attacking us and civilian populations are getting caught in the crossfire," he said.
Sudanese response
The Sudanese government denied barring the UN's humanitarian envoy Jan Egeland from the war-torn Darfur region, but instead claimed his visit was being delayed because of "popular sentiment".
"Egeland was not barred from visiting Darfur but was only asked to postpone the visit due to the growing popular sentiment against the UN for its plans of deploying foreign forces in Darfur," said information ministry official, Bekri Mulah.