KHARTOUM, Sudan, May 11, 2004 (AP) -- Sudan swore in a presidential committee Tuesday to investigate allegations of gross human rights abuses in the western Darfur region, where rights groups say the government and allied militia are carrying out a campaign of ``ethnic cleansing.''

Officials rejected the accusations Tuesday, saying a United Nations report alleging government complicity with a fierce Arab militia was false. Khartoum chided the rights groups for not writing about violations by the autonomy-seeking rebels the militia is fighting.

State-run radio station Omdurman said the committee would have broad access to all government documents and would report directly to President Omar el-Bashir. It is headed by former Chief Justice Dafallah Hajj Yusuf.

``As regards the rapes and sexual harassment, the government would like to stress that those types of crimes are totally rejected by the government, and they are against the values and morals of Sudanese society,'' the foreign ministry said in a statement Tuesday. ``The government reaffirms its commitment to deal with the utmost firmness and firm-handedness with this type of crime.''

On Friday, Human Rights Watch issued a report accusing government troops, working with Arab militiamen, of driving more than 1 million black Africans from their homes in a campaign of bombing, burning and rape that it called ``ethnic cleansing.''

Bertrand Ramcharan, the acting U.N. high commissioner for human rights, after briefing the U.N. Security Council on Friday, blamed the militias for a ``scorched-earth policy'' and spoke of ``repeated war crimes and crimes against humanity.'' He said the government was supporting the militia but stopped short of directly blaming the government for the atrocities.

The foreign ministry statement Tuesday denied that the violence in Darfur had ethnic causes, saying the government and the militia were simply trying to put down a rebellion.

``The government, forced by the escalation of the rebellion, had appealed to the citizens, all of them, to come to the support of the armed forces in containing the violence and the destructive activities carried out by the rebellion movement,'' the statement said.

``That was a general call, to which response varied from the various tribes without any discrimination, and this shows the falsehood of the claim that the government has adopted a racial attitude in this respect.''

The aid group Medecins Sans Frontiers - Doctors Without Borders - said Tuesday that the 60,000 refugees who have fled to neighboring Chad are at severe risk of hunger and disease and appealed for a ``massive mobilization of humanitarian aid'' in Chad as well as in Darfur itself.

The group, in a statement, said refugee camps are severely overcrowded and there isn't enough food to go around. It said thousands of refugees have no access to clean drinking water and that ``the level of malnutrition is now climbing every week.''

Sudan's government accused aid groups and journalists of holding the government responsible for human rights violations while failing to publicize similar violations by the autonomy-seeking rebels the militias are battling.

``There are clearly double standards in handling these questions,'' Humanitarian Affairs Minister Ibrahim Hamid Mahmoud said. ``Those recent reports have failed to mention anything about the rebellion being behind all those atrocities.''

The foreign ministry also said the reports failed to take into account the role of economic sanctions imposed on Sudan for sponsoring terrorism, saying those have contributed to poverty that has helped spark the violence.