The United Nations says its investigators have discovered 17 mass graves in the central Democratic Republic of the Congo, increasing the number to 40 documented in an area that witnessed clashes between the army and a local militia.
The UN said in a statement issued on Wednesday that the graves were reportedly dug by Congolese army after fighting with Kamuina Nsapu militia in Kasai Central province in late March.
"At least 74 people, including 30 children, were reported to have been killed by soldiers as a result of these clashes," the statement added.
The government has not commented on the report, but it has previously rejected the notion that soldiers have used disproportionate force against militia fighters and claimed the militia had dug the sites.
The Kamuina Nsapu uprising has become the most serious threat to President Joseph Kabila, whose refusal to step down following a defeat in the latest polls stoked chaos in the vast central African country.
Kabila's presidential term expired on December 19, 2016, but ruling officials have effectively prolonged his mandate until 2018, claiming that the government would not be able to arrange elections before then.
The government of Kabila reportedly reached an agreement with opposition parties to end the political crisis in the country over his decision to stay in power. Under the accord struck on December 30, 2016, by political parties in the Democratic Republic of the Congo, Kabila will leave office following elections due to be held by the end of 2017.
The fighting between Congolese troops and militia has escalated after government forces killed their chief tribal leader, Kamuina Nsapu, in late August 2016. More than 400 people have been killed since then.