Jan Pronk said an ethnic cleansing campaign in 2003 and 2004 had been successful and a larger, more sophisticated and mobile force was needed to help end the continuing rapes and killings and stop the groups of 500 to 1,000 militia on camel and horseback that still attack villages at least once a month.
"Looking back at three years of killings and cleansing in Darfur we must admit that our peace strategy so far has failed," he told the U.N. Security Council. "All we did was picking up the pieces and muddling through, doing too little too late."
Decades of low-level tribal clashes over land and water in the vast western Darfur region erupted into large-scale violence in early 2003 when ethnic African tribes took up arms, accusing the Arab-dominated central government of neglect.
The government is accused of responding by unleashing Arab tribal militias known as Janjaweed to murder and rape civilians and lay waste to villages. It denies the charge.
An estimated 180,000 people have died in the upheaval, many from hunger and disease.
Pronk briefed the council a day after the African Union's Peace and Security Council accepted in principle the need to transform its 7,000-strong peacekeeping force in Darfur into a U.N. peacekeeping force.
The AU council extended the AU force's mandate until March 31, authorized consultations with the U.N., and said a final decision would be taken by ministers at the end of March, Tanzania's U.N. Ambassador Augustine Mahiga told reporters.
The AU force has made a significant difference where its troops have been deployed. But it has been hampered by a shortage of funds, troops, and equipment and its mandate has been limited to monitoring an April 2004 cease-fire that is regularly broken by all parties and offering limited protection to civilians.