A new UN report has alleged that Rwanda's defence minister is effectively commanding a rebellion in the Democratic Republic of Congo.
The confidential report, leaked to Reuters agency, says Uganda is also backing the M23 rebels, who have been fighting the DRC's army since April.
The document builds on a UN report published in June which accused Rwanda of supporting the insurgents.
Rwanda and Uganda strenuously deny supporting the rebellion.
The BBC's Barbara Plett at the UN says the latest report by the UN Security Council's Group of Experts provides more details of Rwanda's alleged continued involvement.
It says M23 leaders "receive direct military orders" from Rwanda's chief of defence staff, Gen Charles Kayonga, "who in turn acts on instructions from the minister of defence", Gen James Kabarebe.
It also says Kigali has supplied the M23 with heavy weapons and stepped up recruitment for the group.
The report - seen by Reuters news agency on Tuesday - says army units from Rwanda and Uganda have helped M23 expand its control of territory in the war-torn east of DR Congo.