The senior UN envoy to Sudan has said that a deal to end the country's 21-year-old civil war must be followed by moves towards peace in Darfur.
Jan Pronk called for fresh negotiations between warring parties
Jan Pronk told the Security Council there is "political momentum" towards peace in Sudan's western region, but that violence could easily re-emerge.
Sudan's government have signed a peace deal with rebels in southern Sudan, but progress in Darfur has been slow.
Militias and rebels in Darfur are re-arming, Mr Pronk warned the council.
"We may move into a period of intense violence unless swift action is taken," Mr Pronk said, adding that he had asked the UN to deploy human rights observers to the region.
The African Union will send 150 of a promised contingent of 800 troops to Darfur, he added.
About 70,000 people have died and two million have been made homeless in Darfur, a desert area the size of France, since government-backed Arab militias began a violent campaign against black Africans in the region.
In his speech to the Security Council, Mr Pronk hailed the agreement to end the civil war in southern Sudan as a major achievement.
But he warned that Sudan was unlikely to enjoy any tangible 'peace dividend' while conflict continues in Darfur.
Reports from the region since the signing of the peace deal in southern Sudan have suggested that troops are being redeployed to Darfur from areas now classed as peaceful.
Colonel Omar Adam, leader of the Justice and Equality Movement (Jem, a rebel group in Darfur, told the BBC that Sudan's government is "preparing for war".
"The parties must be persuaded, by a combination of pressure and assurances from influential (UN) member states, that it is truly in their interests to respect the ceasefire and pursue a settlement through peaceful means," Mr Pronk told the Security Council.
He proposed that both sides pull back their forces to positions held in early December in an effort to "diminish the urge to steal, loot and kill".