"According to USAID, there could be 300,000 people dead in Darfur by the end of the year, and that's if aid gets to them rapidly.
"If aid does not get there quickly, USAID is warning that a million people could die in Darfur by the end of this year. So the need to get the Sudanese government to react and to end this is very, very urgent right now," Armanpour said.
Aid agencies estimate about 2 million people are in urgent need of food and medical aid.
The 18-month conflict in Sudan began when black African factions in Darfur rose up against the Sudanese government, claiming discrimination in the distribution of scarce resources in the large, arid region.
Since then, government-backed Arab militias, called Janjaweed, have gone on a rampage, destroying villages, killing and raping.
As many as 30,000 people have been killed, and 1 million people have been forced to flee their homes.
Arab countries, meanwhile, on Sunday said the Sudanese government needed more time to end the crisis in Darfur.
The 22-member Arab League, which held an emergency meeting Sunday in Cairo, Egypt to discuss the Sudan situation, also rejected "threats of military intervention in the region or imposing any sanctions on Sudan," AP reports.