What is happening in the Democratic Republic of the Congo?

At least 200,000 people have fled their homes in eastern Congo in the last three months. Ban Ki-moon, the UN secretary general, has warned of a humanitarian crisis of "catastrophic dimensions". There is fear of a return to full-scale war in a country still recovering from years of conflict.

Why has fighting flared up?

Laurent Nkunda, a renegade general and ethnic Tutsi, has accused the Congolese government of failing to protect Tutsi people from Hutu militias who escaped to Congo after taking part in the 1994 Rwandan genocide in which 500,000 Tutsis were killed.

Nkunda, who broke away from the national army last September after it absorbed his forces, has been fighting the government. Violence has reached new levels in the last few months. This week, hopes of some sort of political deal received a boost when the rebels reversed course and agreed to meet the governor of North Kivu, Julien Paluku, after earlier rejecting talks on grounds he did not represent the central government in Kinshasa.

Nkunda recently threatened to take the war all the way to Kinshasa, Congo's capital, on the other side of the country.

How serious is Nkunda's threat?

His forces are much better trained and equipped than the government troops, who are notorious for turning their guns on civilians and fleeing when faced with a real threat.

The Congolese army is a motley collection of defeated army troops, rebels and militia groups left over from back-to-back wars from 1997 to 2003 that left an estimated 5 million people dead. It is disjointed, undisciplined, demoralised and poorly paid, with the lowest-ranking soldiers getting little more than $20 (£12) a month.

Nkunda, who has been implicated in numerous war crimes, is believed to command about 5,500 highly trained and disciplined fighters. The rebellion that overthrew the longtime dictator Mobutu Sese Seko began in the east.

Does Nkunda have outside support?

UN security officials and some diplomats in the region believe Rwanda is giving him ammunition and other material support. Rwanda denies this, but the general does serve Rwandan interests, as he heads the only force in eastern Congo willing to take on the Democratic Liberation Forces of Rwanda (FDLR), a group led by Hutus blamed for the Rwandan genocide.

The Congolese government, led by Joseph Kabila, accuses Rwanda of using Nkunda as a proxy to exercise control in eastern Congo, where it has financial interests in illegal mining.

What does Rwanda say?

Rwanda's president, Paul Kagame, argues Congo must confront the Hutu rebels who control large tracts of the east of the country. Rwanda claims they are intent on overthrowing the Tutsi-led government in Kigali. Joint military action by Congolese forces and the FDLR against Nkunda has fuelled Rwandan suspicions that Kinshasa is not serious about confronting these armed Hutu groups.

What is the UN doing?

The UN has 17,000 peacekeepers in Congo, its largest mission in the world, but Monuc, as it is called, is overstretched. The inability of the UN to stop the fighting in a diamond-rich region where people are desperately poor has fuelled resentment. Civilians have been repeatedly displaced by rebel and army attacks since the official end of the war in 2003.

Thousands of demonstrators attacked the UN headquarters in Goma, smashing cars and office windows, at the height of the fighting in October. UN troops have been sucked into the latest violence, using helicopter gunships against the rebels.

How are peacekeepers coping?

The UN force is in disarray. Its commander, Lieutenant General Vicente Diaz de Villegas of Spain, resigned in October after seven weeks in the job, citing personal reasons. Unnamed UN officials say the general had criticised the lack of a coherent strategy, mandate and resources. The UN is sending an extra 3,000 troops following the latest upsurge of fighting, but expectations that the European Union might send an interim force to bolster 5,000 UN peacekeepers in North Kivu have faded as several European officials said immediate prospects of doing so were unlikely.

Monuc is worried about another area in eastern Congo - the district of Ituri, where Congolese militias have been stepping up their activities for the past two months.

What is the solution?

The International Crisis Group thinktank says that in the long term Congo must develop a plan with Rwanda and the UN to isolate and capture the FDLR's Hutu leaders responsible for the Rwandan genocide.

It says those who were not involved in the killings and are willing to demobilise should be offered resettlement in the Congo or integration with the Rwandan army.