Congo's government and Rwanda-backed rebels said on Thursday they would send delegations back to Qatar for peace talks, as Washington pushes for an end to fighting that could help unlock billions in mining investments.

M23 holds more territory than ever before in eastern Congo after staging a lightning advance earlier this year.

The fighting, the latest flare-up in a conflict with roots in the Rwandan genocide three decades ago, has killed thousands of people and displaced hundreds of thousands more.

U.S. President Donald Trump's administration is trying to broker a peace deal between Rwanda and Congo that would bring billions of dollars of Western investment to a region rich in tantalum, gold, cobalt, copper, lithium and other minerals.

Qatar is hosting a separate but parallel mediation effort with delegations from the Democratic Republic of Congo government and M23.

Last week, the Rwandan and Congolese foreign ministers signed a peace accord in Washington, pledging to implement a 2024 deal that would see Rwandan troops withdraw from eastern Congo within 90 days.

The top diplomats also met with Trump, who invited Congolese President Felix Tshisekedi and Rwandan counterpart Paul Kagame to Washington to sign a package of deals that Massad Boulos, Trump's senior adviser for Africa, dubbed the "Washington Accord".

Speaking to reporters on Wednesday, Boulos said the Trump administration would "love" to hold that meeting at the end of July. But he also said U.S. officials hope to have a deal in Doha finalised by then.

SLOW PROGRESS

At a press conference on Thursday, their first since last week's signing ceremony in Washington, an M23 official said rebel delegates would return to Doha but accused Kinshasa of not taking the process seriously.

"Since the signing of the Washington agreement, we have been contacted three times by the Qatari mediator to resume dialogue," said Benjamin Mbonimpa, one of the M23 delegates who has taken part in the Doha dialogue.

The rebels are still insisting on progress on preconditions such as the release of imprisoned M23 fighters and the reopening of banks in rebel-held territory, he said.

Congo's presidency said in a statement to Reuters that government delegates were also returning to Doha.

The latest report by a panel of United Nations experts, obtained this week by Reuters, said Rwanda has exercised command and control over M23 during their advance.

Rwanda has denied backing M23 militarily, and a government spokesperson said this week the report "misrepresents Rwanda's longstanding security concerns" in eastern Congo, notably the presence of ethnic Hutu militiamen linked to the 1994 genocide.

Despite remaining hurdles to ending the long-running conflict, Boulos said on Wednesday he was "optimistic" because Tshisekedi and Kagame were serious about reaching a deal.