The United Nations on Monday protested what it said was a decision by Sudan to bar the U.N.'s top humanitarian official from visiting the capital and the troubled western Darfur region.

Jan Egeland, U.N. under-secretary-general for Humanitarian Affairs and Emergency Relief, said the government was trying to prevent him from seeing the deteriorating situation in the troubled Darfur region.

A Foreign Ministry official, speaking on condition of anonymity because he was not authorized to speak to the media, denied that Egeland had been barred from visiting.

A statement from the U.N. mission in Sudan said Egeland's flight into Sudan was not given authorization to land Sunday and that Sudanese officials had expressed opposition to his visit.

Egeland had been scheduled to visit southern and western Sudan from Sunday to Thursday to assess relief operations.

He did visit southern Sudan, which is administered by the Government of Southern Sudan, a partner of the Khartoum government that has its own leadership.

Egeland said he was told that visiting Khartoum and Darfur, in the Muslim north of the country, would be too sensitive because publications in his nation, Norway, were among those that published offensive cartoons of Islam's Prophet Muhammad.

"They claim that my nationality is a problem because of the cartoons and me being a Norwegian. This is just an excuse," he told The Associated Press by telephone. "I can only believe that they don't want me to see how bad the situation has become for the civilian population in South Darfur, in West Darfur."

He noted that he had been barred from visiting Darfur in 2004 "when ethnic cleansing was at its worst."

The United Nations has described Darfur as the site of the world's gravest humanitarian crisis. The 3-year-old conflict setting the Arab-dominated government and militias against ethnic African tribes has left some 180,000 dead — most from disease and hunger — and displaced another 2 million from their homes. Sudan's government and rebels in Darfur have made little headway in peace talks in Abuja, Nigeria.

President Omar al-Bashir said in a speech to parliament Monday that resolving the Darfur conflict was his nation's top priority.

"The peace that we have received with joy (in southern Sudan) remains incomplete until we achieve a solution in Darfur," he said.

He said the government would work to end the suffering of civilians and reach a political settlement that included all parties involved in the conflict.

"There cannot be a solution that ignores the rights of anyone or suppresses anyone. A permanent solution is the one that embraces all and resolves all the problems of Darfur," he said.

Egeland said he had been supposed to bring more resources to humanitarian workers who, he complained, were finding it increasingly difficult to reach civilians affected by the violence.

He called the ban part of "an endless string of constant administrative obstacles to our work," saying non-governmental organizations trying to work in Darfur were finding it hard to receive work permits, fuel and other necessities.

"My biggest worry is that all our achievements and advances — in one of the biggest and most effective humanitarian operations anywhere in a war situation — are now being undermined," Egeland said.

NATO's chief diplomat said Monday that the alliance planned to increase support for African peacekeepers in Darfur, but he again stressed that the deployment of NATO troops was not an option.

Secretary General Jaap de Hoop Scheffer said NATO was considering increasing training, planning and transportation support for the African Union peacekeeping force in Darfur, and a U.N. mission that may replace it in September.

"That can very much be done without speaking of a NATO force," he said. "It's the African Union, it's the U.N. which are the guiding organizations."

The U.N. mission's statement said the governor of South Darfur, one of the western states scarred by the conflict, had stated his opposition to Egeland's visit. It also quoted Sudan's representative to the United Nations in New York as stating that Egeland would not be welcome in Darfur or Khartoum.

Mission spokesman Khaled al-Hitti said it was "unlikely" that the Sudanese government would change its mind about letting Egeland resume his planned itinerary in Darfur and Khartoum.