"The three-fold drop in mortality is a clear demonstration that the assistance provided by the Ministry of Health and by the international community has made a dramatic impact in Darfur. However, we must consolidate the results and be vigilant to avoid [a] worsening of the situation," the Federal Minister of Health of Sudan, Ahmed Osman Bilal, said in a statement on Monday.

The survey revealed that the crude mortality rate was around 0.8 deaths per 10,000 people per day in northern, western and southern Darfur - below the threshold of one death per 10,000 people per day usually observed in humanitarian crises.

A similar survey, conducted a year earlier, showed a crude mortality rate of 1.5 per 10,000 people per day in North Darfur, and 2.9 in West Darfur.

Despite this positive development, humanitarian agencies remained cautious and warned against an overly optimistic interpretation of the figures.

"One of our concerns is that, due to ongoing insecurity, there is potentially a risk of bias, as the United Nations has no access to where the war is," Paul Foreman, head of mission of the Dutch branch of Medecins Sans Frontieres (MSF) said on Tuesday.

"Overall figures may diminish the fact that there are pockets of extreme suffering, many times the emergency threshold," he noted.

In North Darfur, injury remained an important cause of death, accounting for nearly a third of the total deaths, particularly among men between 15 and 35 years of age, the survey found.

Nearly 50 percent of mortality among children in West Darfur was related to diarrhoea, a preventable illness.

"The combination of crowded conditions in the settlements, shortage of clean water, inadequate latrines, insufficient soap, and the mire caused by rain-soaked mud mingling with excreta, have combined to make hygiene an impossible goal for people living in small, tarpaulin-covered huts, and these conditions need to be solved," said Guido Sabatinelli, the WHO Representative in Sudan.

Manuel Aranda da Silva, the UN Humanitarian Coordinator in Sudan, added a word of caution: "Deaths due to malaria could rise, as the rainy season is approaching and preparedness for malaria control needs to be stepped up urgently."

Preventable causes of death, such as diarrhoea, required consolidation and expansion of water and sanitation interventions, Da Silva pointed out.

According to the survey, deaths from measles were relatively low after the successful vaccination campaign last year. A follow-up campaign is planned for July.

"Our concern all along has been that people are existing in survival mode, and surviving on food aid," said the communications coordinator of the International Committee of the Red Cross in Sudan, Paul Conneally, on Tuesday.

"It is still not a good scenario to have a substantial part of the population in camps and dependent on humanitarian aid for their survival," he commented.

The war in Darfur pitted Sudanese government troops and militias - allegedly allied to the government - against rebels fighting to end what they described as marginalisation and discrimination against the region's inhabitants by the state.

UN Secretary-General Kofi Annan estimated in his latest report to the Security Council on Darfur that over a third of the total population - more than 2.5 million people, including nearly 1.9 million internally displaced persons (IDPs) - had been affected by conflict and drought.

"It is important that people can go about their lives, move around safely again and resume normal economic activities in Darfur," Conneally stressed.

The survey, conducted by the Sudanese Ministry of Health, UN agencies and NGO partners, with the technical guidance from the WHO, was carried out from mid-May to mid-June.

Approximately 26,000 people were interviewed, including IDPs in camps, those not in camps and other residents affected by the conflict.