Darfur is creeping closer to catastrophe, with rape and violence on the rise, UN Secretary-General Kofi Annan said yesterday.
In the report to the Security Council, Mr Annan said a May peace deal was not being followed, and that humanitarian access is at its lowest level since 2004.
Sudan's armed forces, as well as rebel factions and the militias, continue to violate international human rights law and humanitarian law with impunity, he said.
Letter to UN from government of Sudan
"It has now been three months since the Darfur peace agreement was signed," Mr Annan wrote. "However, instead of reconciliation and building of trust, we are witnessing intensified violence and deeper polarisation. The region is again on the brink of a catastrophic situation.
"Unless security improves, the world is facing the prospect of having to drastically curtail an acutely needed humanitarian operation."
A key stumbling block to the peace so far has been President Omar al-Bashir's rejection of an August Security Council resolution that would allow the United Nations to take control of and significantly expand a peacekeeping force in Darfur, run so far by the African Union.
In a letter sent to several nations, Mr al-Bashir's government said: "In the absence of Sudan's consent to the deployment of UN troops, any volunteering to provide peacekeeping troops to Darfur will be considered as a hostile act, a prelude to an invasion of a member country of the UN."
US Ambassador John Bolton called the document an unprecedented rebuff to the council. "This is a direct challenge to the authority of the Security Council in its efforts to alleviate the tragedy in Darfur and clearly requires a strong response by the Security Council," he said.
In a separate letter to Mr Annan, Mr al-Bashir himself repeated his position that the government would allow the UN to help support the African Union peacekeepers.
The African Union force, which has about 7,000 troops, is meant to monitor a peace deal signed between the Sudanese government and the rebels in May and intended to end the fighting that has left more than 200,000 dead and displaced some 2.5 million since 2003.