Government forces backed by UN troops have defeated the M23 rebel movement that threatened towns in the eastern Democratic Republic of Congo, diplomats at the United Nations said.
"Practically all M23 positions were abandoned yesterday, except a for small triangle at the Rwandan border," Martin Kobler told the UN Security Council by video-link, according to diplomats.
The French ambassador to the United Nations, who was at Kobler's closed door briefing, confirmed his report.
"We can say today that the M23 is finished, militarily," Gerard Araud told reporters. "Most of the positions held by the M23 have been retaken by Democratic Republic of Congo forces."
Araud and other diplomats expressed hope that defeat on the battlefield would convince the rebel faction to return to peace talks.
Kobler, the civilian special representative in charge of the UN stabilization mission in the DRC, was speaking after Congolese government forces backed by UN troops carried out an offensive.
Troops from the UN peacekeeping mission MONUSCO have a mandate to conduct operations against rebels in the region of Goma, capital of the restive province of North Kivu.
A Tanzanian UN soldier was killed in the fighting, but the rebels were rolled back and local civilians are overjoyed, Kobler said, according to officials present at the closed door meeting.
He said that the M23 had abandoned a key position on Mount Hehu near the Rwandan border, reportedly adding: "It is practically the military end of the M23."
The mainly Tutsi M23 movement emerged in April 2012 after a mutiny by former rebels who had been taken into the Democratic Republic of Congo army under a 2009 deal.
Rebels accused Kinshasa of failing to keep the terms of that deal, then on-off talks in the Ugandan capital Kampala failed after the government refused to give an amnesty to about 80 rebel leaders.
The M23's numbers were limited, but the movement, which allegedly received support from neighboring Rwanda, was seen as a threat to stability in a region with long history of conflict.
Rwanda's UN ambassador, Eugene Richard Gasana, alleged that 21 shells had fallen on the Rwandan side of the border during the fighting and that two civilians had been killed and 10 wounded.
He said that 15 wounded M23 fighters had crossed into Rwanda and been handed over to the Red Cross and that 1,000 refugees had fled the fighting.
"Rwanda will be forced to take action if Rwandan lives continue to be jeopardized," he warned, according to diplomats who were at the briefing.
"Rwanda will not tolerate for much longer violations of its territorial integrity," he said, according to the officials, alleging that Rwandan Hutu FDLR rebels were operating alongside Congolese forces.
Kobler, according to diplomats, confirmed some shells had fallen on Rwandan soil and said the United Nations would take steps against the FDLR once the M23 threat was dealt with.