“A group of experts monitoring the implementation of UN sanctions in the Democratic Republic of the Congo said it had interviewed 18 Burundian fighters in the DRC’s South Kivu Province,” reported the Voice of America (VOA).

They all told the experts that they had been recruited in the Mahama Refugee Camp in eastern Rwanda in May and June 2015, and were given two months of military training by instructors, who included Rwandan military personnel, according to the UN experts.

VOA said the report released on Thursday quoted the fighters as saying they trained at a camp in the Rwandan forest and were instructed on the use of “grenades, anti-personnel and anti-tank mines, mortars and rocket-propelled grenades.”

The fighters were transported around Rwanda in the back of military trucks, often with a Rwandan military escort.

The rebels then entered the Democratic Republic of the Congo (DRC) after crossing the Rusizi River in small groups from Rwanda, using fake Congolese identification cards.

“The monitors said the fighters told them their ultimate goal was to remove Burundian President Pierre Nkurunziza from power,” reported VOA.

Nkurunziza’s third term in power, which began in April 2015 and is widely viewed as unconstitutional, has brought political chaos to Burundi, resulting in the deaths of hundreds of people and the forced flight of hundreds of thousands more with analysts fearing a new civil war.

In December Nkurunziza told a visiting UN Security Council delegation that threats against Burundi were not from inside the country but from outside.

“The Rwandan government must be told to stop,” said Nkurunziza.

The Rwandan government has dismissed Burundi’s accusations.

VOA reported that “Rwanda’s Ambassador to Brussels Olivier Nduhungirehe, who is vocal on social media, tweeted: “‘Mass graves, sexual terrorism, torture, extrajudicial killings, hate speech; and @BurundiGov wants to convince us that it’s #Rwanda’s fault!’”

However, the UN Security Council remains unconvinced at Rwanda’s protests of innocence.

On Thursday Russia’s Deputy Envoy Petr Iliichev told reporters the allegations against Rwanda were troubling and the council would have to look at the UN report.

ANA