Sudan and the UN

Sudan blocks the UN from investigating the situation in Darfur.

Sudan has prevented the United Nations' top humanitarian official from visiting refugees from the troubled Darfur region, who have fled to Chad.

The government did not give a plane carrying Jan Egeland permission to fly over Sudanese territory to reach Chad.

How about flying around Sudan to get to Chad? Is that a possibility? Or is the message Sudan sending one that they do not want the UN interfering in its internal matters, even though they're neither solely internal (with the violence spilling over into neighboring countries), nor is the actions Sudan taking with respect to human rights even close to what anyone should consider acceptable. Sudan is trying to hide its involvment in the genocide of its citizens in Darfur at the hands of the janjaweed. Khartoum doesn't seem to mind the violence much, either, and by going out of its way to keep the UN from interviewing refugees, seems to think that they might be implicated in the violence directly.