Q&A: DR Congo's M23 rebels
Rebel fighters in the Democratic Republic of Congo have threatened to march on the capital, Kinshasa, after capturing the eastern city of Goma.
The rebel spokesman said they were ready to topple President Joseph Kabila.
Some 500,000 people have fled their homes since the rebellion began in eastern DR Congo, a region plagued by violence for years.
Who are the rebels?
The group is made up of fighters who deserted from the Congolese army in April following a mutiny.
They are mostly from the Tutsi ethnic group, a minority in eastern DR Congo.
They are 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 is accused of war crimes by the International Criminal Court.
Their movement is called M23 in reference to 23 March 2009, when the CNDP signed an agreement with the Congolese government agreeing to be integrated into the national armed forces.
Why have they rebelled?
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 in the army, were not paid enough and that the military lacked vital resources - and soldiers were going hungry.
But analysts believe the real reason for their rebellion stems from comments made by Congolese President Joseph Kabila in January, who under pressure from the ICC, said the Congolese authorities would put Gen Ntaganda on trial.
What do the rebels hope to achieve?
The fighters have spent the last six months organising themselves in the hills and dense bush of North Kivu.
According to a report by UN experts, they have new uniforms and arms - and have been recruiting men in the areas under their control. They are believed to have 1,200 to 6,000 fighters.
They now control towns like Rutshuru and Bunagana, on Uganda's border, and areas of the famous Virunga National Park - as well as the major city of Goma, on the shores of Lake Kivu.
The M23 said it had taken Goma to make the government sit down at the negotiating table with the group.
But their exact intentions remain unclear.
Since capturing Goma, they have threatened to march south to another important city in eastern DR Congo, Bukavu, and to carry on to the capital, Kinshasa - 1,600km (1,000 miles) to the west.
There is even speculation that they want to create a separate state, "Republic of Volcanoes", named after the volcanoes in the region.
Who are the M23 rebels?
- Named after the 23 March 2009 peace accord which they accuse the government of violating
- This deal saw them join the army before they took up arms once more in April 2012
- Also known as the Congolese Revolutionary Army
- Mostly from minority Tutsi ethnic group
- Deny being backed by Rwanda and Uganda
- Believed to have 1,200 to 6,000 fighters
- International Criminal Court indicted top commander Bosco "Terminator" Ntaganda in 2006 for allegedly recruiting child soldiers
- The UN and US imposed a travel ban and asset freeze earlier this month on the group's leader, Sultani Makenga
Could they really take Kinshasa?
Well, it would take a long time to march across the country. But it has been done before - by Laurent Kabila, father of DR Congo's current president, Joseph, who at the time was backed by Rwanda. It took him and his fighters several months to walk through the jungles
But most analysts seem to think the small group of M23 fighters is unlikely to go this far - they may just consolidate their hold on parts of the east. Rwanda would also come under even more international pressure if they were seen as trying to overthrow the government of another country.
However, some analysts have suggested that the army, embarrassed by its defeat in Goma might try to oust President Kabila.
Do they have other backers?
Eastern DR Congo is rich in resources and minerals like coltan - essential for mobile phones - and mining is a lucrative way for rebels to make money.
But there are also allegations that DR Congo's neighbours are aiding the rebellion.
A report by a UN panel of experts said the rebels were being backed by Rwanda and Uganda - allegations both countries have vehemently denied.
It said that M23 leaders received "direct military orders" from Rwanda's defence ministry.
Kigali is widely seen as having backed armed groups in the east of DR Congo as a way to fight Hutu rebels who fled there after Rwanda's 1994 genocide when some 800,000 people died.
The Rwandan government, led by President Paul Kagame - a former Tutsi rebel commander who took over after the genocide - sees the Hutu militias in eastern DR Congo as a threat to Rwanda's stability.
It has been accused of using militias as proxies in an on-going battle for the region, which provides a buffer zone against the ethnic Hutu rebel groups.
The M23 has also denied any Rwandan backing.
"It's a lie, it's Kinshasa propaganda. Kinshasa can talk a lot, so when they're feeling the heat they try to defend themselves and that's why they say Rwanda, they say Uganda, tomorrow they will say United States or England - that's how it is," Col Makenga told the BBC after capturing Goma.