The top U.N. envoy to Sudan (search) warned the Security Council Thursday that the vast region of Darfur (search) could easily descend into anarchy with warlords in control unless African Union (search) troops deploy quickly and peace negotiations speed up.

The 20-month conflict in the western region is changing in character, with the government not fully in control of its forces and a leadership crisis within the rebel movements, Jan Pronk said.

The envoy accused both sides of violating an April cease-fire agreement and seeking more territory in Darfur, which is about the size of France.

While there was slow progress on the political front in October, Pronk said, violence and insecurity increased and in recent days "the situation deteriorated and tension rose to a level unprecedented since early August."

"Fighting is breaking out in more and more places. Parties are provoking one another. Militias are ganging up. Governmental authorities are not able to exert a moderating influence, or they respond with untimely and even counterproductive measures," he said.

"If this negative trend is not reversed it is a recipe for disaster," Pronk warned. "If the fighting continues crops will fail. Then the whole population of Darfur will become dependent on humanitarian assistance."

The United Nations has called Darfur the world's worst humanitarian crisis, saying the conflict has claimed 70,000 lives since March — mostly through disease and hunger.

Violence started after two non-Arab rebel groups launched attacks in February 2003. Originally a clash between black African farmers and Arab nomads over the distribution of scarce resources, the conflict has grown into a counterinsurgency in which pro-government Arab militia have raped, killed and burned the villages of their enemy.

An international commission appointed by U.N. Secretary-General Kofi Annan (search) began work on Oct. 25 and has three months to study human rights violations and determine whether a genocide occurred in Darfur. Sudan also faces the threat of U.N. sanctions.

According to a monthly report from Pronk, which was sent to the council Wednesday by Annan ahead of the briefing, the estimate of people affected by the conflict rose during September from 1.8 million to 2 million and was expected to continue climbing.

The increase stems mainly from the growing number of people who have fled their homes, now 1.6 million, the report said. A further 400,000 people are in need of humanitarian assistance.

"Darfur may easily enter a state of anarchy; a total collapse of law and order," Pronk warned.

He said the government had "co-opted paramilitary forces" to fight the rebel groups but could not longer count on their obedience.

"The border lines between the military, the paramilitary and the police are being blurred," Pronk told the 15-nation Security Council.

"Within the rebel movements, there is a leadership crisis. There are splits. Some commanders provoke their adversaries by stealing, hijacking and killing, some seem to have begun acting for their own private gain," he said, adding "we may soon find Darfur is ruled by warlords."

The U.N. envoy suggested a three-pronged approach.

Official and self-selected political leaders must be held accountable "for ongoing violations of agreements and further human misery," he said, and armed groups must be told that their rebel status "does not exonerate them from a moral obligation towards their people."

The expanded African Union force must deploy rapidly "to effectively deter violations," Pronk said, urging the Security Council to consider new ways to increase financial and logistical support to get troops where they're needed most.

Political negotiations on Darfur and on ending a separate 21-year civil war between the government and rebels in southern Sudan also must be stepped up, he said.

The Security Council will hold a rare meeting on Nov. 18-19 in Nairobi, Kenya, where talks to end the civil war are taking place.

Pronk also urged the council to press government and rebel negotiators holding separate talks in Nigeria to adopt a declaration of principles and a time frame and detailed agenda for political negotiations on Darfur by the end of the year.