As Rwanda-backed rebels strolled through the streets of eastern Democratic Republic of Congo's second-largest city, President Felix Tshisekedi's office claimed it was actually still controlled by his army and "valiant" allied forces.

Rebel forces have been seen in the center of Bukavu, the second largest city in the eastern Democratic Republic of Congo (DRC), on Sunday, residents told CNN, as the fighters push to expand their foothold in the mineral-rich region.

The ongoing crisis in the eastern Democratic Republic of Congo continues to escalate, with tensions involving the Congolese government and the M23 rebel group

The UN human rights chief accused Rwanda-backed rebels who seized a second major city in eastern Democratic Republic of Congo (DRC) of killing children and attacking hospitals and warehouses storing humanitarian aid.

The M23 movement, supported by some 4,000 Rwandan soldiers, according to U.N. experts, now controls large tracts of troubled eastern Congo. Its rapid advance has sent tens of thousands fleeing.