Fighting between M23 rebels and Democratic Republic of Congo government forces has displaced hundreds of thousands of people in the east of the country since April and damaged relations with Congo's neighbors.
The reports of support for the rebels by officials in neighboring Rwanda have stoked fears of a slide back into broader central African conflict in a region that has long been a tinderbox of ethnic violence.
Here is a look at the rebels and the violence in Congo's vast eastern region:
* Mutineers have been fighting under the banner of the so-called M23 movement, which refers to a March 2009 peace deal that ended a previous rebellion in North Kivu in eastern Congo which the rebels say has since been broken. The group's official leader is Colonel Sultani Makenga but the latest bout of violence was sparked by former rebels who, after being integrated into the Congolese army, took to the bush again after the government said it would arrest another commander, General Bosco Ntaganda, known as "The Terminator".
* Ntaganda was a senior leader of several previous Congolese rebellions and is wanted by the International Criminal Court (ICC) on charges of war crimes and use of child soldiers in an earlier conflict in Congo. Thomas Lubanga, his co-accused, in March became the first person to be found guilty by the ICC and was sentenced in July to 14 years in jail. Ntaganda has denied the charges. With the backing of Rwanda, which experts say had supported the CNDP and other rebel groups in Congo, Ntaganda overthrew then-CNDP leader Laurent Nkunda and guided the insurgent group to the 2009 peace deal. He was then seen by both governments as a guarantor of a subsequent fragile peace that held until earlier this year.
WHAT'S HAPPENING NOW?
* Congo's president, Joseph Kabila, has been pressured into calling for Ntaganda's arrest as part of efforts to repair ties with the international community after his 2011 re-election, in a vote widely viewed as flawed by foreign observers.
* The capture of the town of Rutshuru, days after M23 fighters seized the mineral-transit town of Bunagana, raised fears again for Goma, the provincial capital that was nearly taken by rebels in 2008. Reports have put the rebels as close as 50 km (30 miles) from Goma, prompting U.N. peacekeepers backing Congolese troops to reinforce the city to protect its 800,000 inhabitants.
* Aside from the M23, there are a number of other local and foreign armed groups that also continue to operate in Congo's east, despite the presence of some 17,000 U.N. peacekeepers.
Sources: Reuters/Human Rights Watch/www.cfr.org/www.globalwitness.org/UN reports/www.crisisgroup.org (Reporting by David Cutler, London Editorial Reference Unit)