Q&A: DR Congo's M23 rebels
The M23 rebels have brought havoc to eastern Democratic Republic of Congo since April 2012 but have now ended their insurgency after the government said they had been defeated.
At least 800,000 people have fled their homes and at one point, there were fears a new regional war could break out, with accusations that Rwanda and Uganda were backing the rebels - charges both countries denied.
The advances by the Congolese army follow changes in the military structures and the intervention of a brigade of UN troops with a tough mandate.
Who are the rebels?
The group is made up of fighters who deserted from the Congolese army in April 2012 following a mutiny.
They are mostly from the Tutsi ethnic group, a minority in eastern DR Congo but with ties to Rwanda's leaders.
They were led by several top-ranking officers who were members of a former militia called the CNDP - including Col Sultani Makenga and Gen Bosco Ntaganda, who faces war crimes charges at the International Criminal Court.
Their movement is called M23 in reference to a 23 March 2009 peace deal, which the CNDP signed with the Congolese government.
Why did they rebel?
The rebels, also known as the Congolese Revolutionary Army, say the government has not lived up to its promises in the 2009 deal.
They say they were mistreated after being integrated into the army, were not paid enough and that the military lacked vital resources, with soldiers were going hungry.
But analysts believe the real reason for their rebellion stems from comments made by Congolese President Joseph Kabila in January 2012, who under pressure from the ICC, said the Congolese authorities would put Gen Ntaganda on trial.
Where is he now?
Gen Ntaganda, known as "The Terminator", gave himself up to the US embassy in Rwanda in March 2013, after losing a power-struggle within the M23.
He has since been transferred to the ICC in The Hague.
Is that why they are now on the back foot?
The internal rifts probably didn't actually make much difference.
Most analysts point to two far more significant developments: Reduced Rwandan support for the M23 and the intervention of a tough new brigade of UN troops.
Although this was always denied by Rwanda, UN investigators have long accused Rwanda of backing the M23.
This led several donors to cut financial and then military aid to Kigali and the UN says Rwandan backing to the M23 has now fallen off.
Meanwhile, the UN has sent a force of some 3,000 well-equipped troops with a tougher mandate than any other peacekeeping force, tasked with disarming and "neutralising" rebels forces in eastern DR Congo.
Their use of helicopter gunships against the rebels is credited with making a huge difference, paving the way for the army to retake the territory seized by the rebels in 2012.
Why did the UN send the extra troops?
The UN has had a huge mission - currently some 18,000 troops - in DR Congo for many years but the unrest never seems to end.
Many Congolese have derided them as "tourists" for many years and in 2012, they were unable to stop the M23 from seizing the regional capital, Goma, before they pulled out under international pressure.
But they remained camped on the outskirts of Goma until their recent reverses.
So why would Rwanda back rebels in DR Congo?
The unrest in eastern DR Congo goes back to the 1994 genocide in Rwanda.
After killing some 800,000 ethnic Tutsis and moderate Hutus, some of the militias fled into DR Congo (then called Zaire) as Tutsi rebels seized power in Kigali.
Ever since, the now Tutsi-dominated government in Rwanda has sought to wipe out the Hutu militias, accusing them of planning to destabilise Rwanda.
Rwanda has used several militias, often headed by Congolese Tutsis, to attack the Hutus, analysts say. And the M23 is merely the latest of these.
So is this the end of almost two decades of conflict in DR Congo?
That is the hope.
So it is possible that after international attention has waned - and if the Congolese government does not take action itself against the Hutus - then Rwanda could start backing another group.
And until the Congolese state is strong enough to master its vast territory, two-thirds the size of Western Europe, armed groups could always be tempted to seek to control its mineral wealth.
Eastern DR Congo is rich in resources and minerals like gold and coltan - essential for mobile phones.
In theory, these should mean the area's people are hugely wealthy but so far, they just seem to have attracted a long history of looters.