The UN High Commissioner for Human Rights, Louise Arbour, has urged the International Criminal Court to take more robust action over war crimes and crimes against humanity in the Darfur area.
Ms Arbour, who recently returned from a visit to the region, said rape, violence and abuse remained largely unabated since her previous visit in 2004.
She said there was a need to ensure accountability 'for crimes of a magnitude that some have qualified as genocide'.
The ICC launched an investigation into the events in Darfur in June 2005 and has said it has gathered evidence of killing, rape and destruction.
But the Sudanese government has vehemently maintained its right to handle the cases domestically, and established its own special court for this purpose last June.
However, despite Sudanese government assurances, Ms Arbour has insisted there is no evidence that anyone in a position of authority has been called to account.
After speaking to displaced women in Darfur, the UN Commissioner said she was shocked to find that rapes 'on a large scale' were being carried out in the camps, in a near systematic manner that prevented the women from seeking out food.
The women described their attackers as government-backed Janjaweed Militia, and asserted that men could not leave the camps because they would be killed.
Sudanese officials told Ms Arbour that they could not pursue rape allegations because the women were unable to identify their attackers and there was therefore 'no case' for prosecution.
Plight of Sudanese refugees in Chad
The UN Emergency Relief Co-ordinator, Jan Egeland, has complained that the world has forgotten about the 200,000 Sudanese refugees in neighbouring Chad.
During a visit to camps in eastern Chad, Mr Egeland said aid agencies had received only a fraction of the funds they needed to help the displaced Sudanese living there.
The refugees fled from the Darfur region in western Sudan to escape attacks by government-backed militias.
Mr Egeland told reporters that the Chadian army had retreated, leaving the refugees open to attacks from armed groups.
The conflict in Darfur broke out in February 2003, when indigenous ethnic groups launched a rebellion against Khartoum that was brutally repressed by militia linked to the regime.
An estimated 2.4 million people fled their homes.
