KINSHASA, Congo (AP) -- Rebels entrenched in the hills above one of eastern Congo's largest cities declared a ceasefire on Friday and began retreating from the frontline, the first indication that a joint United Nations and Congolese offensive might be gaining the upper hand in the conflict.
But in a sign that the conflict could spill over the border, a large convoy of military vehicles loaded with troops, tanks, artillery cannons and heavy weaponry was seen leaving the capital of Rwanda, Congo's neighbor to the east, which is accused of funneling arms and troops to the M23 rebels.
Rwandan leaders said they were acting to defend their border, after shells and rockets, allegedly fired from the Congolese side of the Rwanda-Congo border landed in Rwandan territory, killing a mother and seriously wounding her 2-month-old baby.
Late Thursday, Rwanda's Foreign Minister Louise Mushikiwabo said on her official Twitter account "Deliberate shelling of Rwandan territory unacceptable. Rwandan civilians are falling victims. A provocation that will no longer B tolerated." On Friday, she Tweeted: "Rwandan troops are not in DRC (yet); when they are, you will know."
The heightening of hostilities with Rwanda comes as Congolese and United Nations troops appear to be making significant gains against the M23 rebels. The U.N. intervention force has pounded the M23 rebel positions with attack helicopters and artillery fire.
Reached by telephone, M23 president Bertrand Bisimwa said that his group was retreating and declaring a ceasefire in order "to give peace a chance."
"We have decided to decree a unilateral ceasefire and we have started pulling our forces out of Kanyaruchinya," he told The Associated Press. "This announcement, which was made unilaterally, is meant to allow the Congolese to return to the negotiating table."
In a statement Friday, United Nations spokesman Martin Nesirky said that -- in addition to the village of Kanyaruchinya -- the rebels had also vacated the village of Kibati and the area of Kibati Heights.
Congolese military spokesman Col. Olivier Hamuli confirmed that the area of Kibati had been retaken, and said that combat was ongoing in Kibumba, around 30 kilometers (18 miles) from Goma.
"They announced (their ceasefire) when they realized that they were losing on the ground. I am just back from the frontline and they have suffered heavy losses. They have abandoned an arms depot with heavy weapons," Hamuli said. "They even abandoned a military vehicle which proves that they are quitting because if they are just retreating they should take their armaments with them."
In Congo's capital, Kinshasa, government spokesman Lambert Mende said the call for a ceasefire does not go far enough.
"It's our opinion that the only interesting proposition would be to see M23 demobilized, and to see them dissolve and cease all military action. Any other proposal is unacceptable," said Mende, Congo's minister of information.
The fighting, which began on Wednesday last week, has so far claimed the lives of one U.N. peacekeeper as well as at least 10 Congolese soldiers and 14 civilians who died from the shelling on either side of the Congo-Rwanda border.
All but one of the civilian deaths from shelling was on Congolese territory, with the exception of a rocket which fell in the Rubavu district of Rwanda, just across the border, Thursday, killing a woman.
Angry Rwandan officials claim the rocket was fired on purpose by Congolese troops in order to drag Rwanda into the conflict -- a claim that was seen as deeply cynical by some, given the mounting evidence that the M23 rebels are in fact a Rwandan proxy force.
A recent United Nations Group of Experts report describes how Rwandan soldiers sneak across the forested border in groups of up to 30 men to join the ranks of the M23, a group which is almost entire Tutsi, the ethnic group of Rwanda's ruling class. Previous U.N. reports have described the logistical support Rwanda is providing, including night vision goggles.
Goma, a Congolese city of 1 million located on the Rwandan border, briefly fell to the M23 rebels last year in a humiliating blow both to the Congolese military, which barely put up a fight, and the thousands of United Nations peacekeepers stationed in the region, who stood by as the rebels entered the strategic town. They said they could not intervene because their mandate only permitted them to protect civilians.
In response, the U.N. created the new intervention brigade which is authorized to directly combat the rebels.
Rukmini Callimachi contributed to this report from Dakar, Senegal. Associated Press writer Jason Straziuso also contributed to this report from Nairobi.
Follow Rukmini Callimachi on Twitter at www.twitter.com/rcallimachi
Copyright 2013 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.