GOMA, DR Congo - Fighting between rebels and government soldiers in the east of the Democratic Republic of Congo entered a third day Sunday, sources said, in a fresh flare-up that has prompted international calls for restraint.
"Some fighting is still going on in Kibumba," some 25 kilometres (12 miles) north of the regional mining hub of Goma, a UN official told AFP.
A high-ranking army officer confirmed the fighting in the area, but the rebel M23 movement could not be reached for comment on the reports.
Kibumba, high on a plateau at an altitude of nearly 1,800 metres (6,000 feet), is an outpost that commands access to rebel territory further north.
The rebels withdrew to Kibumba after a major offensive by the army backed by the UN force MONUSCO in late August pushed the frontline back some 15 kilometres.
Fresh fighting broke out around Kibumba on Friday, the heaviest since August, with each side accusing the other of initiating the violence and claiming to win ground.
The new clashes come less than a week after Kinshasa and the M23 rebels announced that peace talks in the Ugandan capital Kampala had collapsed.
The negotiations were part of a framework both sides agreed to last year, following a rebel offensive that saw the M23 briefly take control of Goma.
The United Nations has since deployed a special brigade of 3,000 African forces with an unprecedented offensive mandate but observers remain wary of an escalation that could draw in the entire region.
Late Saturday, the army claimed to have captured Kibumba, but the M23 dismissed the claim as "propaganda", while the MONUSCO officer described it as a partial takeover.
The MONUSCO officer said Sunday that other fighting was under way on a second front that opened Saturday on the road between Mabenga and Kahunga, further north, where the army recently beefed up its positions.
UN chief Ban Ki-moon's top envoys to the conflict, Mary Robinson and Martin Kobler, issued a statement voicing grave concern over the fresh fighting and calling for "maximum restraint".
The United States and European Union also voiced alarm, urging all parties to return to negotiations.
Rwanda, which lies just a few miles from the areas where the fighting took place Saturday, on Friday accused the Congolese army of firing three shells over the border into its territory and threatened to retaliate.
Kinshasa has long accused Kigali of pulling the strings behind the rebellion and UN experts have even said that the M23's "de facto chain of command" was topped by Rwanda's defence minister.
Rwanda has vehemently denied accusations that it is arming, financing and supporting the rebels by sending some of its own forces to the frontlines in DR Congo.
Rwanda in turn has accused Kinshasa of coordinating attacks against Kigali with the FDLR, a DR Congo-based Rwandan group which includes the remnants of Hutu militia who carried out the 1994 genocide.
EU foreign policy chief Catherine Ashton called on "all actors in the region to prevent further escalation and internationalisation of the conflict".