Congolese Tutsi rebels threatened on Sunday to advance into U.N.-monitored buffer zones in eastern Congo after refusing to sign a declaration ending hostilities with the government, the rebels and mediators said.
Following several days of U.N.-backed talks in Nairobi, Kenya, the rebels led by renegade General Laurent Nkunda also declined to recommit to their own unilaterally declared cease-fire in Democratic Republic of Congo's North Kivu province, Reuters reported.
This raised fears of a collapse of a fragile truce and of a renewal of fighting which had already driven more than a quarter of a million civilians from their homes since late August, triggering a humanitarian emergency in North Kivu.
Nkunda's National Congress for the Defence of the People (CNDP) accused government soldiers and their allies, which include Rwandan Hutu rebels, of sending troops and militia into disengagement zones intended to separate the belligerents.
"This is not behaviour that we will tolerate for very long," Bertrand Bisimwa, a spokesman for Nkunda, told Reuters.
"If these zones are not respected, we have the right to go back on our decision. We will be obliged to retake them to secure them," he added.
U.N. peacekeepers in Congo said they had detected no Congolese army movements into the buffer zones.
After launching their offensive in late August, Nkunda's battle-hardened fighters routed President Joseph Kabila's army and captured swathes of territory in North Kivu before declaring a unilateral cease-fire in late October. This ended major battles with government forces but the CNDP continued to skirmish with pro-government Mai-Mai militia and Rwandan Hutu rebels.
The talks in Nairobi aimed at cementing the cease-fire and forging a lasting peace appeared to be floundering.
"The CNDP refused to sign a joint declaration of cessation of hostilities with the government of the DRC," U.N. and African Union mediators said in a statement released on Sunday.
"Furthermore, the CNDP has declined to recommit itself to its own existing unilateral cease-fire declaration," they said, although Congo's government reaffirmed its own November 18 truce.
The peace talks were due to resume on January 7.