Laurent Nkunda: This picture taken on November 10, 2008 shows Tutsi rebel leader Laurent Nkunda making a point as he speaks with the international press in the mountains of North Kivu. YASUYOSHI CHIBA/AFP/Getty Images
Some 4,000 Rwandan troops this week entered DR Congo to help fight rebel forces in the area. Correspondents say Gen Nkunda's arrest removes one obstacle to peace but other rebel groups remain active.
Nkunda had been Rwanda's ally in eastern DR Congo - a Tutsi, like Rwanda's leaders, he guarded their Western flank against attacks from the Hutu forces who fled there after the Rwandan genocide of 1994. But in mid-November Rwanda shifted its position, announcing it would work with the Congolese to destroy the Hutu rebels.
DR Congo has issued an international warrant for Nkunda's arrest following past accusations that his forces had committed atrocities. Rwanda has not yet said whether it will hand over its former ally. Some of Nkunda's forces - perhaps as many as 2,000 - are still said to be loyal to him.
Nkunda's CNDP launched a major offensive in August 2008, which displaced more than a quarter of a million people in North Kivu and raised fears of both a humanitarian crisis and a wider regional war. Correspondents say this may have been Gen Nkunda's undoing, by bringing huge international pressure on all sides to end the conflict in DR Congo.
Human rights group have accused CNDP forces, along with those of the government, of numerous killings, rapes and torture. All sides in the Congolese conflict have also been accused of using the fighting as a pretext to loot eastern DR Congo's rich resources of minerals such as gold, tin and coltan, used in mobile phones. Some five million people are estimated to have died as a result of almost 15 years of conflict in DR Congo, following the Rwandan genocide.
In November, the United Nations Security Council voted to send 3,000 more troops to the Democratic Republic of Congo following renewed fighting in the country's east. The increase means the peacekeeping mission, MONUC, will have about 20,000 troops and police on the ground - the biggest UN force of its kind.
A peace deal was signed in Goma between the government and various rebel groups in January 2008. Although he signed the deal, Nkunda has refused to disarm while Rwandan Hutu rebels still operate in the area.
Coverage on The World:
Nkunda arrested (January 23)
Nkunda profile (November 21)
Congo and your cell phone (November 21)
Call for more peacekeepers (November 13)
More fighting in Congo (November 4)
Update from Goma (November 3)
The humanitarian crisis (October 31)
Chaos in Congo (October 30)
Congo's violent past (October 30)
Renewed fighting in Congo (October 16)
Why did the fighting break out again last year?
Nkunda has always said he is fighting to protect his Tutsi community from attack by Rwandan Hutu rebels, some of whom are accused of taking part in the 1994 genocide.
The Congolese government has often promised to stop the Hutu forces from using its territory, but has not done so. The latest deadline was apparently the end of August - just when the fighting blew up again.
But eastern DR Congo is rich in natural resources such as gold and coltan, which is used to make mobile phones. Some say the fighting is really over control of these resources.
The Congolese government has accused Rwanda of backing Gen Nkunda, with troops and heavy artillery. Rwanda denies the claims but it has twice invaded its much larger neighbor in recent years. Rwanda's president is Paul Kagame - a former Tutsi rebel who ended the genocide, in which some 800,000 Tutsis and moderate Hutus were killed.
The Congolese army has been accused of working with the Hutu rebels both on the battlefield and in exploiting the region's mines. So it is plausible that Rwanda could be using Nkunda's forces to put pressure on DR Congo to finally live up to its promises to disarm the Hutu militias.
The UN has 17,000 peacekeepers in DR Congo - its largest mission in the world. Some Congolese accuse the UN of doing nothing - just being "tourists" - and have attacked their offices in Goma.
UN troops in Goma
But the UN mission has sent helicopter gunships to help stop the rebel advance on Goma and has asked for extra forces to help stop the fighting.
What about the civilians?
Aid workers are extremely worried about tens of thousands of people in the area. All sides are accused of carrying out horrific atrocities against civilians, in particular mass rape.
Many of those who have fled to Goma are sleeping in the open, relying on local people and aid agencies for food.
Many more are likely to be caught up in the fighting in the region's picturesque rolling hills. The UN fears that some people are dying from malnutrition.
