The United Nations on Wednesday expressed concern over reprisal attacks against ethnic Tuaregs and Arabs in Mali, where a French-led intervention recently routed Islamist rebels.
The United States meanwhile called for a rapid transition to a UN peacekeeping force that can impose order in the country, amid doubts over the ability of Malian forces to keep the rebels at bay.
UN Under-Secretary-General for Political Affairs Jeffrey Feltman said that while "arbitrary acts of violence" against members of the Tuareg and Arab communities had recently slowed, "there is still a risk of reprisal."
"Worryingly, it appears from reports that new patterns of human rights violations have emerged, including retaliatory attacks based on ethnicity."
The remarks came as he updated the 15-member UN Security Council about the situation in the troubled West African nation.
The French-led intervention quickly drove out Islamist insurgents who had seized much of the country, but significant pockets of resistance remain in the Ifoghas mountains as well as in the northern cities of Gao and Timbuktu.
The Islamists had swept into power in the north on the back of a Tuareg rebellion, and since they were driven back there have been reports of mob lynchings and other revenge attacks by black Malians against Arabs and Tuaregs.
The United Nations estimates that about 470,000 people have fled the fighting, including more than 290,000 who are internally displaced and about 177,000 residing in Mauritania, Niger and Burkina Faso.
Feltman said there will be another 750,000 people in need of immediate food assistance and 660,000 children at risk of malnutrition this year, including 210,000 at risk of severe acute malnutrition.
"Humanitarian access has improved in some parts of the country," Feltman said, but in other areas, particularly in Timbuktu and Gao, the situation remains "highly volatile."
His remarks came one day after the European Union began a full overhaul of Mali's ill-prepared army to help it take the place of foreign troops.
Mali's military fell apart last year when the extremists seized the country's vast and arid north before terrorizing locals with amputations and executions performed under a brutal interpretation of sharia, or Islamic law.
Paris plans to hand over responsibility to the Malian army and a UN-mandated African force of 6,300 troops, known as AFISMA, in the coming weeks.
UN chief Ban Ki-moon has proposed putting in place a UN stabilization mission mostly recruited from the AFISMA troops, as well as a mostly French "parallel force" to undertake counterterrorism missions.
The plan gained immediate backing from the United States, with US Ambassador to the United Nations Susan Rice saying the transition to a blue-helmeted force should take place "as soon as security conditions permit."
"Its role ought to be to stabilize the liberated areas and assist the Malian state in protecting civilians," Rice told reporters.
"We expect that there will continue to be French and other partners of Mali engaged in robust antiterrorism operations in the far north and we will support that," said Rice, adding that they should do so separately from the UN force.
Feltman also stressed that a "clear distinction" be maintained between the two forces, explaining that "any blurring of the distinction would place severe constraints on the ability of UN and other personnel to safely do their work."