A UN human rights mission has accused Sudan's government of orchestrating and taking part in international crimes in Darfur.
The United Nations mission, led by Nobel peace prize laureate Jody Williams, was dispatched by the UN Human Rights Council to investigate charges of widespread abuse in Sudan's vast western region, where revolt broke out in 2003.
"The situation is characterised by gross and systematic violations of human rights and grave breaches of international humanitarian law," the mission said in a report to the Human Rights Council.
UN human rights mission report
"The mission further concludes that the government of Sudan has manifestly failed to protect the population of Darfur from large-scale international crimes and has itself orchestrated and participated in these crimes," the report said.
The Darfur genocide has killed tens of thousands of people and driven 2.5 million from their homes as rebels, charging the government in Khartoum with neglect, battle pro-government Arab militias.
Humanitarian agencies say they face growing difficulties in getting help to the desperately needy, and increasingly aid workers themselves are targets of the violence.
Khartoum rejects the genocide term and says those numbers are exaggerated. It blames rebel groups that refused to sign up to a 2006 peace deal for the worst abuses and says Western media has blown the conflict out of proportion.
The decision to send the six-person team to Sudan was taken by the UN's human rights watchdog only after a bitter debate last December.
Some Arab and African countries on the 47-state body had resisted singling out Sudan for special attention.
The Sudanese government, which is resisting calls for UN peacekeepers to be deployed in Darfur, at first agreed to co-operate but then refused to issue visas to the mission.
The mission urged the UN Security Council to take urgent action to protect the civilian population in Darfur, including the deployment of peacekeepers.