Pillay arrived in the Central African Republic to get a first-hand account of ongoing violence. She said from the CAR capital, Bangui, large-scale killings have halted but the security situation is far from clam.
Seleka, a Sunni coalition, staged a rebellion in December 2012 and toppled the government in March. Pillay said anti-balaka, a Christian militia, was now responsible for the bulk of the bloodshed.
"The inter-communal hatred remains at a terrifying level," she said in a statement. "Children have been decapitated, and we know of at least four cases where the killers have eaten the flesh of their victims."
The U.N. Security Council in December authorized the deployment of French troops to CAR to help support an African Union peacekeeping mission. Pillay said that despite the effort, the situation in CAR is extremely dangerous.
"In short, although CAR has received international attention, that attention is far from commensurate with the needs," she said.
Catherine Samba-Panza, a Christian and former mayor of Bangui, was appointed in January to lead the country to general elections next year. She took over after Michel Djotodia, a leader from Sunni rebel movement Seleka, resigned.