(Recasts with comments by U.N. officials) By Joe Bavier GOMA, Congo, Sept 7 (Reuters) - United Nations peacekeepers struggled to preserve a confused and shaky ceasefire in eastern Democratic Republic of Congo on Friday after a renegade general accused government troops of breaking the truce. U.N. officials described the situation in North Kivu province as tense a day after the U.N. Mission in Congo (MONUC) announced what turned out to be a limited ceasefire around the town of Sake, 20 km (12 miles) from the provincial capital Goma. "MONUC has intervened twice this morning to stop fighting but for now the clashes have stopped," Sylvie Van Den Wildenberg, the U.N. spokeswoman in North Kivu, said. Earlier, renegade General Laurent Nkunda, whose Tutsi fighters have battled the Congolese army for nearly two weeks in volatile, racially-mixed North Kivu, accused government troops of breaking the ceasefire with an attack in Rutshuru district. But U.N. officials played down the reported clash in the remote Virunga National Park. They said the truce appeared to be holding around the strategically important town of Sake, up to where Nkunda forces had advanced on Thursday, sending thousands of refugees fleeing towards Goma. "Tense -- that is the word," the U.N. military spokesman in Kinshasa, Gabriel Debrosse, told Reuters. Earlier, he said U.N. peacekeepers had warned Nkunda's fighters they would be fired on if they tried to advance. Nkunda told Reuters he was still ready to respect the ceasefire. "We want to negotiate, but it seems for them (the army) it is a strategy to buy time to reinforce," he said. Debrosse said several soldiers and Nkunda fighters were wounded in the Rutshuru clash, which was reported to have occurred east of Rumangabo. The Congolese army gave no details. The worsening fighting in eastern Congo has been a setback to efforts by President Joseph Kabila, who won landmark elections late last year, to achieve lasting peace across the former Belgian colony, scarred by a 1998-2003 war. HUMANITARIAN SUFFERING Nkunda, who first led a revolt in 2004 but signed a short-lived peace deal in January, says he is fighting to protect his Tutsi people in eastern Congo against attacks by Rwandan Hutu rebels he says are backed by Kabila's government. The Great Lakes region which includes eastern Congo is a tinderbox of wars, ethnic conflicts and border disputes. Kabila and his Ugandan counterpart Yoweri Museveni were expected to meet in the northern Tanzanian town of Arusha this weekend to resolve a border dispute over oil exploration. The fighting in North Kivu has brought fresh human suffering to an area racked by successive humanitarian emergencies. The U.N. World Food Programme, which is trying to provide emergency rations to refugees, said the upsurge in violence was uprooting more people every day. It estimated 40,000 people had fled in recent days on top of 200,000 displaced since December. The U.N. humanitarian chief, John Holmes, visited civilians who had fled the fighting near Sake on Friday and called for an end to the violence in North Kivu. "I think the politicians of this country, neighbouring countries and the international community in general need to find a political solution as quickly as possible," he said. Nkunda said he would welcome outside mediation. "If the international community gets involved I think we can find a lasting peace," he told Reuters. The latest clash in the Rutshuru district took place in Virunga National Park, a sanctuary for rare mountain gorillas repeatedly attacked by eastern Congolese rebels and militias.