Sudan denied on Thursday a media report that it had sent aircraft camouflaged with marking of the United Nations (UN) to its troubled western Darfur region.

"This report is baseless and totally contradictory to the principles of the Sudanese Armed Force (SAF) and its commitment to these principles and the conventions it had signed," SAF spokesman Osman Mohammed al-Aghbash told reporters.

"This accusation, which is absolutely unacceptable, is closing the door of cooperation between Sudan and the parties which are standing behind the insults against Sudan," he added.

The denial came after the New York Times reported on Tuesday that the Sudanese government had been flying arms and heavy military equipment into Darfur in violation of UN Security Council resolutions.

The report also said that Sudanese military planes had been found painted white to disguise them as UN or African Union aircraft, adding that at least one plane had been camouflaged with the UN marking.

UN Secretary-General Ban Ki-moon has expressed concern over the report, saying that he "will continue to work closely with the Security Council on the issue and will expect full cooperation from the government of Sudan, other governments and all other parties to provide prompt clarification."