A new rebel group in the eastern part of the Democratic Republic of Congo is raising the threat of renewed war in the country, where a fragile reconciliation process is in place following two wars in the last decade. The small United Nations mission in Congo and the beleaguered power-sharing government established last year are having difficulties safeguarding the peace process.

As in 1996 and 1998, when Congo's two previous wars broke out, leading to the deaths of nearly three-million people, trouble is mounting in the eastern Kivu region.

Long-time Africa analyst Alex Vines, at the British Royal Institute of International Affairs, says it could be a repeat scenario leading to the total breakdown of Congo's central authority.

"It wouldn't be unduly alarmist to say that the transitional government is close to disintegrating. [But] this is a really dangerous situation and it's the biggest threat yet that we've seen to the country's fledgling peace," he said.

Dissident Congolese General Laurent Nkunda, who is leading the new rebellion, says he is fighting to protect ethnic Tutsi Banyamulenge people in eastern Congo. He accuses the new Congolese army of committing atrocities against them.

General Nkunda says that since his fighters retreated from the border town of Bukavu last week, ethnic Banyamulenge have been forced to flee despite the presence of the U.N. peacekeeping mission known as MONUC.

"You know what's happening. There is not any Banyamulenge. Their houses are being burned. The international community knew it and MONUC was there when they were burning the houses of Banyamulenge," general Nkunda said.

An estimated 10,000 Banyamulenge have fled to Burundi in recent days. They have been unable to go to Rwanda because that border is closed.

But a Brussels-based activist from the group Human Rights Watch, Stephan Van Praet, says there is evidence that Mr. Nkunda's forces committed gross human rights violations during the previous war in areas under his control, and that this pattern continued when he was in control of Bukavu this month. "Now we see that Mr. Nkunda is again involved in serious war crimes in Bukavu,? Mr. Van Praet said. ?We have similar executions, there was systematic rape, even of children just of three years old, so this circle of violence and impunity is still going on in the region."

Human Rights Watch says government forces also committed atrocities in Bukavu during the recent fighting, including killing 15 unarmed civilians. But a U.N. report released Tuesday said this was not targeted specifically against ethnic Banyamulenge, and it rejected General Nkunda's allegations of systematic persecution. Many ethnic Banyamulenge themselves do not support Mr. Nkunda, and some of them cheered when his forces retreated.

General Nkunda says unless the government in Kinshasa changes the leadership of its army and conducts an investigation into the violence, he will, "liberate eastern Congo and force a decentralized federal system to be put in place." He says his fighting forces are growing every day.

Several thousand of his fighters, who are grouping north and south of Bukavu, wear crisp new uniforms and have heavy artillery. Many, including Mr. Nkunda himself, are remnants of the former Rwanda-backed RCD-Goma rebel group who have refused to integrate into the new national army.

The Congolese government has called for General Nkunda's arrest, as it has since the peace process started, saying he is refusing to relinquish military authority in eastern Congo. It has also accused the ethnic Tutsi-led government in Rwanda of supporting the rebellion and of massing its troops along the border for a new invasion.

Reached on his mobile telephone in Kigali, Rwanda's Foreign Minister Charles Murigande denied the accusations.

"What prompted us to close the border was this baseless allegation that Rwanda sent troops to capture Bukavu, that Rwanda has troops in D.R.C. so we closed the border,? Mr. Murigande said. ?We've called for anybody who wants to come and monitor our border and look for these Rwandan soldiers, arrest them and take them to court and even shoot them on site if they so desire."

But the Rwandan foreign minister adds that the insurgency is probably justified because, he says, there is evidence ethnic Banyamulenge are being persecuted in eastern Congo.

An analyst for the London-based World Markets Research Center, Gus Selassie, says there could also be economic reasons for the new insurgency against Congo's transitional government, which was established after peace talks in South Africa. Mr. Selassie says, during the Congo wars, ethnic-Tutsi Banyamulenge, with the support of Rwanda's army, controlled much of eastern Congo's resource-rich economy, something they might be trying to hold on to.

"Given the Tutsis have pretty much had the run of eastern D.R.C. for the past five years they are very reluctant to give up control of the region under the Pretoria agreement which basically demands them to hand over control to the Kinshasa government and the new national army," Mr. Selassie.

Mr. Selassie and other analysts, and some U.N. officials, agree that the U.N. force in Congo, which has just 10,000 soldiers, is too small to keep the peace against the well-organized insurgents. They also say that the country's new national army, which includes former rebel forces, remains too fragmented to be effective.

Both U.N. and Congolese officials have been trying to negotiate an end to the new rebellion. Earlier this month, a combination of talks, promises and threats prompted the withdrawal of dissident troops from Bukavu, but with General Nkunda's new threats that withdrawal may have been only temporary.

The standing of both the U.N. mission and the Kinshasa government also appear to be increasingly tenuous. U.N. offices throughout the Democratic Republic of Congo have been attacked by angry protesters calling on peacekeepers to fight against the rebels, but U.N. officials say they have neither the force nor the mandate to do that. At the same time, the official residence of President Joseph Kabila has been the scene of repeated fire fights among various armed groups, including several apparent attempts to overthrow him.

According to the peace accord, Congo is supposed to have elections next year, but analysts say the worsening instability appears to be making that less and less likely.