The UN's rights chief on Thursday expressed horror at the level of violence in the Central African Republic, citing cannibalism, child decapitations and gruesome lynchings.
UN High Commissioner for Human Rights Navi Pillay warned that the world's response was alarmingly slow and made a passionate appeal for greater mobilisation.
"The inter-communal hatred remains at a terrifying level," she said at a press conference in Bangui.
"This has become a country where people are not just killed, they are tortured, mutilated, burned and dismembered... Children have been decapitated, and we know of at least four cases where the killers have eaten the flesh of their victims."
The chronically unstable country sank into chaos when rebels who had helped topple president Francois Bozize a year ago went rogue.
The ensuing campaign of killing, raping and looting by the mainly Muslim former rebels prompted members of the Christian majority to form vigilantes known as "anti-balaka" (anti-machete).
France has around 2,000 troops in the country and the African Union three times that number but they have struggled to prevent what the UN has described as ethnic cleansing against the Muslim minority.
Pillay said the military deployment had helped curb large-scale killings of the type witnessed in December and January but warned that much more was needed to pacify the country.
"People continue to be killed on a daily basis, especially by the anti-balaka groups," she said.
An army spokesman in Paris said Thursday that French forces had in recent days engaged anti-balaka militiamen who had been attempting to set up checkpoints on the main road linking Bangui to Cameroon, a lifeline for the country.
- World response 'slow' -
The UN rights envoy said foreign peacekeepers and aid workers faced "terrible dilemmas such as choosing between unwillingly aiding the 'cleansing' of trapped Muslim populations, or leaving them -- against their will -- in places where they are in real danger of being slaughtered en masse."
She said around 15,000 Muslims were trapped in little pockets of territory in Bangui and elsewhere in the country, under international protection.
According to figures from the UN and other relief agencies, nearly a quarter of the country's population of 4.6 million has been displaced in more than a year of conflict.
The French army spokesman, Colonel Gilles Jaron, said that among a few "encouraging signs" was the fact that some of the tens of thousands of people sheltering at the Bangui airport camp for the displaced had begun returning to their homes in recent days.
Navi Pillay said her interaction with the interim administration of President Catherine Samba Panza also offered a glimmer of hope but she warned a much stronger international commitment was needed.
France justified sending troops into its former colony in December by warning that a genocide could be in the making and Pillay hinted that threat may not have fully dissipated yet.
"I am deeply concerned by the slow response of the international community. The vital humanitarian aid effort is deplorably under-funded, with only 20 percent of requirements met so far," she said.
"The international community seems to have forgotten some of the lessons it learned in Bosnia and Herzegovina, Rwanda, Kosovo and East Timor - to mention just a few."
The French general of a European Union force which had been due to deploy this week complained on Wednesday that he did not have enough soldiers.
With the world's eyes firmly trained on the Ukrainian crisis, the largest troop contributor so far -- Georgia, with 150 soldiers -- is not even a bloc member.
Pillay echoed fears by some Central African leaders that a failure to stem the chaos and insufficient international assistance would attract Al Qaeda-inspired groups.
"I cannot help thinking that if the Central African Republic were not a poor country hidden away in the heart of Africa, the terrible events that have taken place -- and continue to take place -- would have stimulated a far stronger and more dynamic reaction by the outside world," she said.
"How many more children have to be decapitated, how many more women and girls will be raped, how many more acts of cannibalism must there be, before we really sit up and pay attention?"