The Democratic Republic of Congo's President Félix Tshisekedi is not taking part in regionally brokered talks aimed at ending the rebel assault on the key eastern city of Goma, state media has reported.

Kigali’s support of former Democratic Republic of Congo president Joseph Kabila could complicate peace talks, while Goma, the capital of North Kivu Province, is under siege by the M23.

The president of crisis-hit Democratic Republic of Congo was set to meet his Rwandan counterpart at an emergency summit on Wednesday, as fighters backed by Kigali appeared on the brink of seizing the key city of Goma.

Rwanda-backed M23 rebels faced pockets of resistance from army and pro-government militia overnight after entering eastern Congo's largest city Goma in the worst escalation of a conflict that has run for more than a decade.

According to reports, the Romanian government and the US intervened to ensure the safe passage of the mercenaries.

Many of the millions of people trapped in eastern Congo's escalating rebellion face a terrible choice: Retreat into Congo's interior and seek the protection of an army in disarray, or cross into nearby Rwanda,

The United Nations says Rwanda-backed rebels captured large parts of eastern Congo’s largest city of Goma including its airport.

Dozens of Romanian security contractors in the eastern DR Congo crossed the border into neighbouring Rwanda on Wednesday to surrender to authorities following days of deadly fighting, according to Kigali.

The Rwanda Defense Force reported escorting hundreds of "Romanian mercenaries" out of the Democratic Republic of the Congo after seizing Goma.

Rwandan-backed rebels strengthened their control over east Congo's largest city, Goma, on Wednesday as columns of Romanian mercenaries hired to fight for Congo entered Rwanda under tight supervision by Rwandan security forces.