Decades of war have devastated Africa's largest country and fresh competition for its resources continue to fuel conflict, said the report by the United Nations Environment Programme said.

"Long-term peace in the region will not be possible unless these underlying and closely linked environmental and livelihood issues are resolved," it said.

In its report, entitled "Sudan post-conflict environmental assessment", the UN agency stressed that desertification and land degradation had been a key source of conflict in impoverished Darfur.

"Northern Darfur -- where exponential population growth and related environmental stress have created the conditions for conflicts to be triggered and sustained by political, tribal or ethnic differences -- can be considered a tragic example of the social breakdown that can result from ecological collapse," the UN said.

The conflict in Sudan's parched western region of Darfur erupted in February 2003 when rebel groups complaining of marginalisation and demanding a greater share of the country's resources took up arms.

According to the UN, the Darfur conflict has left some 200,000 people dead. A bitter two-decade long north-south civil war ended in January 2005, after killing an estimated 1.5 million people.

The report identified a string of critical issues, such as population displacement, desertification, land degradation, deforestation, water projects, chaotic urbanisation and pollution from the country's booming oil industry.