Rwanda on Monday backed DR Congo's military crackdown on Hutu rebels, who accuse the neighbouring nations of trying to "massacre" them and "balkanise" the DRC's volatile east.
The Democratic Forces for the Liberation of Rwanda (FDLR) rebel group operates freely in the North Kivu and South Kivu provinces of the Democratic Republic of Congo where other militias and rebel groups also abound.
"Thanks to the Congolese army, the days of the FDLR are numbered," Rwanda's minister in charge of East Africa, Olivier Nduhungirehe, tweeted.
Rwanda had in September hailed the death of FDLR chief Sylvestre Mudacumura, which was announced by the Congolese army, in a sign of thawing ties between the neighbours.
The FDLR groups former members of the Rwandan army who fled to DR Congo after the 1994 Rwandan genocide in which some 800,000 people, mainly Tutsis, were killed.
The FDLR in a statement on Sunday accused Rwandan President Paul Kagame and his Congolese counterpart Felix Tshisekedi of "concluding a pact ... to massacre Rwandan refugees in the east of DRC."
It also accused the "invaders of the DRC including the Rwandan government ... of trying to occupy the DRC and balkanise the country."
Cardinal Fridolin Ambongo, the archbishop of Kinshasa, last month voiced similar fears about "balkanisation."
"It is up to the government to assume its responsibilities and persuade... neighbouring countries, particularly Uganda, Rwanda and Burundi, to stop pouring people into Congo," he had said.
The influx, he said, was a source of friction in eastern DRC.
The poor and chronically unstable region is in the grip of militias, some of which are historically rooted in armed campaigns against neighbouring regimes.