Gen Laurent Nkundabatware, commonly known by his last name shorter version, Nkunda, leader of the strongest rebel group in eastern Democratic Republic of Congo, has been arrested in Rwanda after fierce fighting betweem his rebel forces and the combined troops of Rwandese and Congolese governemnt.

He crossed the border after resisting a joint Rwandan-Congolese operation to arrest him, both countries say.

Correspondents say it is a startling about-turn by Rwanda, which had been accused of backing Gen Nkunda, turned against him, when he refused to abide by the rules of a ceasefire being mediated by former Nigerian President Olusegun Obasonjo. 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. The operation, marking unprecedented cooperation between the Great Lakes neighbors after years of mutual suspicion and hostility, follows international pressure for an end to more than a decade of conflict in Congo's eastern borderlands.

Regional observers say that Gen Nkunda has been caught in the rapidly changing diplomatic situation in Central Africa. The shifting alliances in the region which now are seeing governments in the region link arms against rebel groups they have hither to sponsored against each other seem to have its origin in the Obama administration. “The regional actors knew from day one when Oboma won the elections. He would not be taken for a ride as the case was with Bush, so they had to act quickly, or they would be reprimanded by the new regime in Washington. This is an effort to appease Washington’s new regime” Said Bzil Mugirangande a Rwandese national based in New York.

Gen 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. Gen Nkunda did not back the new alliance and so became an impediment to Rwandan plans in the region, causing Rwanda to turn on him, our correspondent says.

The decision earlier this month by a group of Gen Nkunda's top commanders to break away and join forces with government troops provided a much need breakthrough for the Congolese government.

The next step is for the joint Congolese-Rwandan force to tackle the FDLR Hutu rebels, some of whose leaders are accused of involvement in the 1994 slaughter in Rwanda of some 800,000 Tutsis and moderate Hutus.

The rebel leader was detained in Rwanda after troops converged on his stronghold in the Congolese town of Bunagana. A Congolese army colonel, who asked not to be named, said Gen Nkunda and rebels loyal to him had fought against Rwandan and Congolese troops when they arrived at Bunagana, a town on the border with Uganda in Congo's North Kivu province

"The ex-general Laurent Nkunda was arrested on Thursday 22 January at 2230 hours while he was fleeing on Rwandan territory after he had resisted our troops at Bunagana with three battalions," a Congolese-Rwandan official statement said. His leadership of his Tutsi rebel National Congress for the Defense of the People (CNDP) group had been challenged this year by dissident rebel commanders who last week ended hostilities with the Congolese government.

The commanders' statement urged Tutsi fighters loyal to Gen Nkunda to disarm and integrate into the Congo government army.

In the joint operation, more than 3,500 Rwandan troops have crossed the border into Congo to join Congolese government forces in trying to disarm Rwandan Hutu FDLR rebels.

According to a BBC report monitored in Kampala,Congolese Information Minister Lambert Mende Omalanga, told the BBC he welcomed the arrest. "I think it is a good achievement for peace and security in this area and this region of Great Lakes," he said.

DR Congo has issued an international warrant for Gen Nkunda's arrest following past accusations that his forces had committed atrocities and Mr Omalanga said he wanted Rwanda to extradite him to face justice in DR Congo. Rwanda has not yet said whether it will hand over its former ally.

The 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.

Neigbouring countries of Uganda and Rwanda, have been accused of entering the Congolese conflict as a pretext to loot eastern DR Congo's rich resources of minerals such as gold, tin and coltan, used in mobile phones. D.R. Congo has won a judgment in the international court worth million against Uganda because of the looting carried out by Ugandan forces.