Some 3,000-4,000 Rwandan soldiers fought alongside M23 rebels in east DR Congo, said a UN expert report seen by AFP Monday, which noted that Kigali had "de facto control" of the group's operations.
The North Kivu province has been in the grip of the M23 (March 23 Movement) rebellion since the end of 2021, with the group seizing swathes of territory in the region and installing a parallel regime in areas now under its control.
Kinshasa has accused Rwanda of backing the Tutsi-led M23 rebel group. Kigali has never acknowledged its troops were operating in the Democratic Republic of Congo.
But the report commissioned by the UN Security Council said the Rwandan army's "de facto control and direction over M23 operations" renders the country "liable for the actions of M23".
Rwanda Defence Force (RDF) military interventions and operations in the Nyiragongo, Rutshuru and Masisi territories -- all in North Kivu -- "were critical to the impressive territorial expansion achieved between January and March 2024" by the M23, the report stated.
In response to AFP's request for comment, Rwandan government spokesperson Yolande Makolo accused the Democratic Republic of Congo of having "consistently threatened war on Rwanda", and said the country "will continue to defend itself".
The report's researchers estimated that at the time of writing in April, the number of Rwandan troops were "matching if not surpassing" the number of M23 soldiers, thought to be at around 3,000.
Until the end of 2023, Rwandan authorities publicly denied that their troops were operating alongside M23 rebels in North Kivu, but has not directly commented since then.
The report contains authenticated photographs, drone footage, video recordings, testimony and intelligence, which it says confirm the RDF's systematic border incursions.
The footage and photos show rows of armed men in uniform, operating equipment such as artillery and armoured vehicles with radar and anti-aircraft missile systems, as well as trucks to transport troops.
Rwandan President Paul Kagame said on June 20 on France 24 "we are ready to fight" against the Democratic Republic of Congo if necessary, although he avoided the question of his country's military presence in the country.
For several months the United States, France, Belgium and the European Union have been calling on Rwanda to withdraw its forces and ground-to-air missiles from Congolese soil and to stop supporting the M23.
The M23 have seized swathes of territory over the past several years, almost completely encircling Goma, the provincial capital of North Kivu, killing scores of people and displacing hundreds of thousands more.
There are already 2.8 million displaced people in North Kivu, according to the UN Office for the Coordination of Humanitarian Affairs.
The report also said that children from the age of 12 have been recruited from "almost all refugee camps in Rwanda" to be sent to training camps in the rebel zone under the supervision of Rwandan soldiers and M23 combatants.
"Recruits aged 15 and above were combat-trained and dispatched to the frontlines to fight," it said.
It added that the recruitment of minors in Rwanda was generally carried out by intelligence officers "through false promises of remuneration or employment," and that those "who did not consent were taken forcefully".
During their offensives the M23 and Rwandan army "specifically targeted localities, predominantly inhabited by Hutus, in areas known to be strongholds of FDLR" - the Democratic Forces for the Liberation of Rwanda.
The FDLR is a Rwandan rebel group formed by former senior Hutu officials behind the genocide of the Tutsi in Rwanda in 1994, who have since taken refuge in DR Congo.
The presence of the group in the eastern DR Congo is considered by Kigali as a threat.
The international community has called for an end to foreign intervention in war-riddled DR Congo and also asked Kinshasa to distance itself from the FDLR.
But the UN report noted that the DRC government has used several "North Kivu armed groups, including the FDLR, to fight M23 and RDF".
This mixture of armed groups fighting alongside the Congolese army is known as the Wazalendo - Swahili for patriots.
The experts who wrote the report accused the Wazalendo of numerous violations of human rights and international humanitarian law.
The experts also said they had confirmation of "active support" for the M23 from members of the Ugandan intelligence services.
This comes even though Uganda's army has been working alongside the Congolese army in its fight against another rebel group affiliated with the Islamic State group, some 100 kilometres (62 miles) north of the area under the control of the M23.
