A UN human rights expert on Friday urged rebels in the war-torn Central African Republic to "lay down their arms" and engage in political dialogue.
"I vehemently condemn the obstinacy of the Coalition of Patriots for Change and other armed groups who continue to spread terror, insecurity and suffering among the civilian population and victims of violations and abuses," Yao Agbetse, the UN independent expert on the situation of human rights in the CAR, said in a statement.
One of the world's poorest countries, the CAR has been torn apart by civil wars for much of the past nine years.
In late 2020, the most powerful of the rebel groups then controlling two-thirds of the country formed the Coalition of Patriots for Change and tried to oust President Faustin-Archange Touadera by launching an offensive on the capital Bangui.
The army managed to repel the attack with alleged help from Russian mercenaries, but the Centrafrican government still struggles to establish its authority in many areas of the vast nation.
After a 10-day visit, Agbetse painted a grim picture of the state of human rights in the country.
He accused a rebel group, the Popular Front for the Rebirth of Central Africa (FPRC), of committing rape and sexual slavery, mostly against girls aged 11-17.
He also alleged the CAR national army and the internal security forces and their auxiliaries had carried out "unacceptable" human rights violations in an attack on the village of Boyo in December last year.
A UN report last month accused government forces and foreign private military contractors of training the militias behind possible war crimes and crimes against humanity in Boyo.
Machete-wielding militia members killed at least 20 civilians in the week-long attack, while five women and girls were raped and 547 houses were burned and looted.
CAR's former colonial ruler France and its allies accuse Touadera of turning to private Russian military group Wagner to shore up his position in exchange for a share of the CAR's mineral wealth.
Agbetse demanded Wagner not prevent the United Nations and its peacekeeping force in the country, MINUSCA, from doing their job.
"The Wagner group must not prevent the deployment of MINUSCA protection operations and not obstruct the investigation of human rights abuses and violations of international humanitarian law," he said.
In March, the UN High Commissioner for Human Rights, Michelle Bachelet, denounced "serious human rights violations" in the CAR, including killings and sexual violence against civilians, committed by rebel groups but also by the military and their Russian allies.