French hard-left leader Jean-Luc Melenchon on Thursday denounced the "expansionist aims" of Rwanda in the Eastern Democratic Republic of Congo (DRC), as fighting flared between rebels and pro-government armed groups.

"I wanted to reaffirm my fraternity with the Congolese people, at a time when they are facing a challenge that is imported," Melenchon said, after a meeting with DRC President Felix Tshisekedi.

It was time for "condemnation of actions disrupting the democratic life of this country, since the resumption of military activities... is taking place at a time when the DRC is organizing its presidential elections".

Elections are due on December 20, with Tshisekedi a candidate.

Independent UN experts, Kinshasa as well as Paris and Washington have accused Rwanda of backing the Tutsi-led M23 rebel group, which has captured swathes of territory in eastern DRC since 2021.

Kigali has denied the accusation.

The conflict has recently intensified around Goma, the capital of North Kivu province, with clashes between M23, the Congolese army, and groups of pro-government fighters.

Fighting has forced almost 200,000 people to flee their homes since October 1, according to the United Nations humanitarian agency.

Melenchon said the M23 rebel movement "articulated by neighboring Rwanda", reflected a "deliberate desire to disrupt... the functioning of democracy in the Congo" and challenge its "sovereignty".

He added that he hoped for a return to a ceasefire and that "Rwanda abandons the expansionist aims that we have heard Rwandan President Paul Kagame declare".

Melenchon arrived in the DR Congo on Tuesday for a one-week stay, after being invited by a university and accompanied by a delegation of three MPs from his France Unbowed party.