The five-year conflict in Darfur may have left as many as 300,000 people dead a steep increase from the previous estimate of 200,000 according to U.N. officials.
Suffering in the Sudanese region is worsening with tens of thousands being displaced from their homes and food rations are about to be cut in half.
John Holmes, U.N. under-secretary-general for humanitarian affairs, mentioned the new estimate in a speech at a U.N. Security Council meeting on the conflict in the western Sudanese region.
A study in 2006 suggested that 200,000 had lost their lives from the combined effects of the conflict. That figure must be much higher now, perhaps half as much again, Holmes said, according to a written text of his remarks.
According to Sudan's U.N. Ambassador Abdalmahmoud Abdalhaleem, the figure was greatly inflated.
The United Nations cautioned reporters that the number was not a scientific estimate but a reasonable extrapolation.
The Darfur, a region that is roughly the size of France, conflict began in early 2003 when ethnic African rebels took up arms against Sudan's Arab-dominated central government, accusing it of discrimination. Many of the worst atrocities in the war have been blamed on the janjaweed militia of Arab nomads allied with the government.
The region now faces a bleak situation where only about 9,000 soldiers and police officers of the authorized 26,000 have deployed.
Abdalhaleem mostly blamed the United Nations for the delay because it had not secured enough helicopters and had not complied with Khartoum's demand that the troops be mostly Africans.