The United States has urged U.N. Secretary General Kofi Annan to visit Sudan's Darfur region, after Mr. Annan criticized the Security Council's approach to ending the violence there.  Frustrations are bubbling to the surface as diplomatic efforts to stop violence in Sudan remain mired in controversy.

Secretary General Annan says conditions in Darfur are deteriorating, even after months of high-profile diplomatic intervention and the arrival of thousands of African Union peacekeepers.

During his end of year news conference Tuesday, Mr. Annan made clear his disappointment at the failure of international peacemaking efforts in Darfur.  Without naming any country, he said he had heard "lots of good intentions" from some member states, and suggested not enough real help has been forthcoming.

Twice he pointed to the Security Council, noting that it bears ultimate responsibility in cases such as Darfur.

"If additional support is needed and additional action is needed, the Council needs to assume its responsibility," said Mr. Annan.  "After all it has ultimate primary responsibility for international peace and security."

Mr. Annan's comments appeared to annoy several Security Council diplomats, who were meeting behind closed doors to hear what they called a "disturbing briefing" on conditions in Darfur.

As he emerged from the briefing, the Deputy U.S. Ambassador Stuart Holliday said Council members take their responsibility seriously. He suggested Mr. Annan should also take a more prominent role in peacemaking efforts.

"I'd like to just point out, however, that the continued engagement of the Secretary General on this question is absolutely critical," said Mr. Holliday.  "We will be engaging with the Secretary General on steps the Council might take and also think it is, it might be, time for him to actually personally see the situation in Darfur again as he did last summer."

Frustration at the failure to end Sudan's civil wars led Washington's U.N. Ambassador John Danforth to complain this month that the Security Council was "getting nowhere".

The Council passed resolutions threatening sanctions earlier this year, but at least two veto-wielding members, China and Russia, are known to oppose implementing them.

The United Nations estimates 70,000 people have died and more than 1.5 million have been forced from their homes over the past 19 months in Darfur. U.N. officials call it the world's worst humanitarian disaster.

The United States has labeled the actions of Darfur's pro-Arab Janjaweed militias "genocide," and demanded that the Khartoum government take action to stop the killing.