The conflict comes amid rising global tensions after Donald Trump’s election, especially between Washington and Beijing, over control of strategic minerals like those present in the Congo.

A conflict that has raged for decades reached a flashpoint this week when rebels backed by Rwanda marched on a key Congolese city in a bid to occupy territory and exploit minerals.

Rwanda's ally Uganda, unhappy about another rebel group in DR Congo that threatens its security, has also been accused of helping the M23 - with its officers also spotted at Tchanzu. The UN experts say Uganda has also supplied weapons, hosted rebel leaders and allowed cross-border movements of M23 fighters - accusations Kampala denies.