UNITED NATIONS — Secretary-General Kofi Annan warned Monday that Sudan's volatile Darfur region faces an increasing threat of complete lawlessness and anarchy and said it is crucial that the government and rebels conclude a peace agreement by the end of the year.

In his monthly report to the UN Security Council, Annan said "a dangerous increase'' in violence in recent months has affected the delivery of humanitarian aid and claimed the lives of civilians and five members of the 6,700-strong African Union peacekeeping force.

"The looming threat of complete lawlessness and anarchy draws nearer,'' he wrote.

Annan said further deterioration can be averted only by rapidly consolidating the progress made at the sixth round of peace talks between the Sudanese government and Darfur rebels which ended in October.

A new round of peace talks in Abuja, Nigeria, was scheduled to begin Monday, but the Sudan News Agency reported Sunday that the talks had been postponed. No reason was given for the postponement.

Annan, whose report was written before the announcement, said a peace agreement before the end of the year was crucial.

It is also imperative that the international community, in co-ordination with the Sudanese parties, start planning immediately to provide assistance needed to ensure the successful implementation of any agreement, he said.

The Darfur conflict began in February 2003 when rebel groups took up arms against the government, accusing it of neglect and repression of Sudanese of African origin.

The government is accused of supporting a counterinsurgency led by Arab militia, known as the Janjaweed, which has been blamed for widespread killing, rape and arson. The Sudanese government denies backing the Janjaweed.

The United Nations estimates that 180,000 people have died in the conflict, mainly through famine and disease. Several million more have either fled into neighbouring Chad or inside Sudan.