The top United Nations envoy to Sudan is warning that violence is on the rise in Darfur. The envoy is urging donor countries to make good on their pledges of aid and peacekeeping troops.

Special envoy to Sudan Jan Pronk says he is encouraged that a January peace agreement between Khartoum and southern rebels remains in place. There had been fears the deal might fall apart following the death of rebel leader John Garang in July.

But Mr. Pronk expressed grave concern about conditions in the western Darfur region, which continues to be plagued by civil war and a humanitarian crisis. 

Briefing the Security Council Wednesday, Mr. Pronk said pressure must be brought to bear on warring factions to reach a comprehensive peace agreement by the end of this year. He described Darfur as a place where rebels and government troops fight it out even while their negotiators are meeting in the Nigerian capital, Abuja.

"Parties sometimes talking and the day after shooting," Mr. Pronk said. "That's not the way to do it. There's not reason anymore to try to solve conflict by further shooting and fighting. Everything can be solved at the negotiating table. And it is possible before the end of the year. Parties have to be serious. And I've asked members of the Security Council to issue a strong statement, We don't accept it any more. We want you to, we demand it."

Mr. Pronk said there has been a surge of violence in Darfur recently, along with rising tensions in the capital, Khartoum.  He noted that only one-quarter of an authorized force of 10,000 African Union peacekeepers are on the ground in Darfur, and said contributing countries must be pressured to dispatch more troops to the region.

A senior U.N. adviser on gender issues told reporters Wednesday women continue to be victims of the conflict in Darfur. Rachel Mayanja, who just returned from a tour of the region, said police patrols have failed to stop the incidents of rape and other violence against Darfurian women.

"Civilian police have started patrols accompanying women to fetch firewood and cut grass," Ms. Mayanja said. "It has been found most of the attacks occur when women go to fetch firewood, so they have designated days when police go with women. And when they have done so they have not been attacked. But in those cases where the women go alone, unfortunately, the attacks continue. And the numbers have not been reduced substantially." 

The Security Council authorized a peacekeeping mission to southern Sudan last year, but has left Darfur to an undermanned African Union force.

Civil war broke out in Darfur in early 2003 when rebels from ethnic African tribes took up arms against the Khartoum government. It descended into what was called the world's worst humanitarian crisis last year after pro-government Arab militia known as Janjaweed unleashed a campaign of ethnic cleansing against villages sympathetic to the rebels.

The special envoy, Mr. Pronk, Wednesday lamented the international community's late response to the Darfur crisis when it broke out. He said quick action by the Security Council two-and-a-half years ago could have prevented the conflict, which is blamed for at least 180,000 deaths, and added "the more it goes on, the harder it will be to change".