An M23 rebel attack on farmers and other civilians in east Democratic Republic of Congo killed 169 people earlier this month, a U.N. body told Reuters, in what would be one of the deadliest incidents since the Rwanda-backed group's resurgence, Reuters reported.

M23 leader Bertrand Bisimwa told Reuters it would investigate but the report could be a "smear campaign".

The U.N. rights body's account has not been previously reported and emerged as U.S. President Donald Trump's administration pushes for peacebetween Congo and Rwanda that it hopes will unlock billions in mineral investments, according to Reuters.