DAKAR African Union peacekeepers from the Republic of Congo operating in the Central African Republic have been accused of abuses, including torture, killings and detentions, Human Rights Watch (HRW) said on Monday.
The allegations - from witnesses, residents and local officials interviewed by HRW during an investigation by its staff - are likely to embarrass the AU peacekeeping mission, which suffered a blow to its legitimacy in April when Chadian forces were accused of killing 30 civilians.
Chad denied the allegation, saying its forces opened fire after being ambushed by Christian "anti-balaka" militia.
About 6,000 AU peacekeepers, known as MISCA, are working alongside French and European Union troops to try to restore order in the nation, where months of ethnic and religious violence have killed thousands and made nearly a million homeless.
HRW said that on March 24 a group of Congolese troops surrounded a house belonging to an anti-balaka general and captured at least 11 people, including four women.
The incident, which took place about 80 km (50 miles) north of Bangui in the town of Boali, followed an attack on a Congolese vehicle by anti-balaka troops.
"The African Union needs to say what happened to the group that was detained and taken by the Congolese peacekeepers," said HRW emergencies director Peter Bouckaert said in a statement.
HRW said that MISCA had agreed to an investigation of the incident which it said could be a violation of international law.
The rights group also said it had received reports that Congolese troops had tortured to death two anti-balaka leaders following the lynching of a Congolese soldier in the northern town of Bossangoa in December.
Central African Republic has been gripped by ethnic and religious violence since northern Seleka rebels, who are mostly Muslim, seized power in the mainly Christian nation in 2013.
Seleka left power in January under intense pressure after 10 months of looting and violence that prompted the creation of the anti-balaka militia.
(Reporting by Emma Farge; Editing by Daniel Flynn and Louise Ireland)