A Burundian human rights group said Wednesday it had identified the locations of 14 mass graves around the country.
The Association for the Protection of Human Rights and Detained Persons (APRODH) added that hundreds of people have disappeared in the east African country since last year. It did not say how many of them could be buried in the mass graves.
The group reported five mass graves in the region of the capital Bujumbura, eight in the north and one in central Gitega province.
Those buried in the graves could include government opponents killed by security forces and soldiers killed during a failed coup attempt in May 2015, according to APRODH.
They could also include members of the youth wing of the ruling party CNDD-FDD, who dug the mass graves and were killed to eliminate them as witnesses, said Pierre Claver Mbonimpa from APRODH.
“Vehicles of the [Bujumbura] city hall, of the police and of the army move bodies to these mass graves," Mbonimpa told dpa.
Government spokesman Philippe Nzobonariba declined to comment, saying police were investigating the affair.
Police spokesman Pierre Nkurikiye said he could not comment on the report because APRODH participated in the coup attempt and is a banned organization.
"These facts do not exist, it is a strategy to influence politically," Nkurikiye said.
Burundi has been rocked by political violence since President Pierre Nkurunziza won a third term in the July 2015 elections, despite a constitutional two-term limit.
Amnesty International had already reported the presence of mass graves in the country, citing witness accounts, video footage and satellite images.