In a report to the Security Council, Mr. Annan says a long-term commitment by the international community is essential to help make secure and to reconstruct the southern part of Africa's largest country, which was torn by war for more than two decades.

But he states that the mission faces daunting logistical challenges: aside from its security problems, southern Sudan is extremely isolated, with "poor communications, few hardened roads or runways and an inoperable railway system," as well as extra transport restrictions during the annual rainy season. Landmines and unexploded ordnances present another risk.

The area covered by the mission – which would be set up under Chapter VI of the UN Charter – is also so large that one of the six proposed operational sectors is the size of Austria and another is equal to the state of New York.

The report to the Council follows last month's signing of a peace deal ending the civil war between the Sudanese Government and the rebel Sudan People's Liberation Movement/Army (SPLM/A) that had raged since 1983. The peace agreement has provisions on power-sharing, some autonomy for the south, and more equitable distribution of economic resources, including oil.

Mr. Annan says a deployment of 10,130 military troops and up to 755 civilian police is necessary, and he voices concern that, despite appeals to at least 100 nations, the UN "has received a very limited number of responses." So far there are enough commitments to meet only the first phase of the planned deployment.

The Secretary-General states that substantial aid is required to resettle refugees and IDPs, with between 500,000 and 1.2 million displaced people expected to return to their homes this year alone. Money is also needed to fund economic development and Norway has agreed to organize an international reconstruction conference.

The civil war in the south has concluded as another continues in the Darfur region in the country's west, where tens of thousands of people have been killed and more than 1.8 million others displaced from their homes during the past two years.

Mr. Annan says "it would be impractical for peace to reign" across all of Sudan before supporting the peace agreement that has been struck in the south, and he expresses hope that the deal will help the Sudanese people resolve their other conflicts.

Jan Pronk, the Secretary-General's Special Representative for Sudan, is expected to brief the Council tomorrow on the contents of the report.