Kivu, the Democratic Republic of Congo's mineral-rich eastern border region, has for years been the focus of armed conflict that has often drawn in neighbouring countries.
Divided into the provinces of Nord- and Sud-Kivu, the region is rich in natural resources – but it is not so much its fertile farmland that is coveted by the rival armed groups as the rare minerals to be had from its lucrative mines.
Sharing borders with Rwanda, Burundi, Uganda and Tanzania, Kivu's volatile political mix is in part due to the way that the violence in some of these neighbouring countries has spilled over into its own territory.
Since the 1994 genocide in Rwanda, when ethnic Hutus went on a 100-day killing binge targeting the Tutsi minority and moderate Hutus, the region has hosted a massive number of refugees who fled the conflict.
Rwandan Hutu militia are also active there, some of them accused of having taken part in the genocide.
Burundian and Ugandan rebels operate there, too, as well as local tribal militia.
With successive waves of both Hutus and Tutsis having settled in Kivu since as far back as the 18th century, the ethnic tensions there remain high.
In the 1980s, the former president of DR Congo, Mobutu Sese Seko, exploited the question of nationality to marginalise people of Rwandan origin there.
It is a measure of how unstable the region is that two recent wars in DR Congo – between 1996 and 1997, then from 1998 to 2003 – both started in Kivu.
And in both, Rwanda – led by the Tutsis of the Rwandan Patriotic Front, who seized control after the genocide – sent troops and supported rebels inside DR Congo.
Its government argued that it needed to ensure its own security, particularly given the presence of the Rwandan Hutu rebels.
In 2001, the rebel Rwanda Hutu forces formed the Democratic Forces for the Liberation of Rwanda (FDLR), which Rwanda and many other observers say includes former participants in the genocide.
Since the end of the second war, several army uprisings in Kivu have involved Congolese Tutsi soldiers.
In 2007 and 2008 the Tutsi Congolese general Laurent Nkunda led an uprising in Nord-Kivu province at the head of the National Congress for the Defence of the People (CNDP).
Backed by Rwanda, Nkunda routed DR Congo government forces in the province and at one point threatened the regional capital Goma.
But then in an unprecedented move, Rwandan and Congolese forces joined forces against the FDLR, while Nkunda was arrested in Rwanda.
But the latest uprising in Kivu, which started in April, is of soldiers who once belonged to Nkunda's now-defunct CNDP.
Integrated into the army as part of a March 23, 2009 peace agreement, they mutinied this year, complaining about pay and conditions. They are known as the M23 movement, after the ill-fated peace deal.
UN experts and campaigners including Human Rights Watch have accused Rwanda of backing this latest uprising.
Rwanda has angrily denied the accusations, accusing the DR Congo of backing the Hutu FDLR in attacks on Rwanda. – Sapa-AFP