The top United Nations envoy to Sudan is warning that the landmark north-south peace agreement could collapse unless the killing in Darfur is stopped.

Special envoy to Sudan Jan Pronk Friday urged The U.N. Security Council to approve his request for 10,000 blue-helmeted U.N. troops to enforce the north-south peace deal signed last month. But he told the council the deal may collapse anyway if a separate conflict in Darfur continues. "I'm convinced that without a solution in Darfur, the north-south will not remain a sustainable peace agreement," he said.

Mr. Pronk briefed the Security Council as ambassadors considered a response to a U.N.-appointed commission that found evidence of ethnic cleansing and war crimes in Darfur.

The council is split over several issues that have delayed the introduction of a draft resolution, and there was no indication Friday if the impasse could be broken.

Diplomats suggested the sensitive issue of prosecuting suspected war criminals might be put aside. The U.N. commission suggested suspects be taken to the International Criminal Court. But the United States, which opposes the court, has rejected that option. Washington favors using a separate tribunal in Arusha, Tanzania.

But while the diplomatic wrangling drags on, Mr. Pronk says he is losing patience with the Sudanese government's failure to stop the activities of Arab militia known as janjaweed, which are suspected of committing atrocities in Darfur.

He said Sudanese leaders had told him they are unable to control the janjaweed. "They come with a statement that they are disciplining, sanctioning military commanders who are acting against their instructions. That is taking place, I have to believe that. I tell them "you have to go further, you have to prevent it," he said.

Mr. Pronk Friday said Sudan's vice-president Ali Osman Mohammed Taha and former southern rebel leader John Garang would come to New York to brief the Council next week. He expressed hope that their presence might push the Council to authorize the U.N. peacekeeping force that could enforce the north-south accord while the Darfur negotiations continue.