With three neighbouring armies already on the ground, a conflict that has simmered in Democratic Republic of Congo’s eastern borderlands for years is evolving into a wider regional war.

M23 rebels, in the latest of a string of uprisings backed by Rwanda, seized the city of Goma in January and went on to make gains across North Kivu and South Kivu provinces.

The region has a history of outside interference. This time, Kinshasa has sought help from Burundi, which dispatched thousands of its troops to try to defeat the rebellion. The position of Uganda, officially in Congo to help the government fight against Islamist militants, is ambiguous as the U.N. has accused it of also backing the M23, which it denies. It has sent reinforcements over the border in recent weeks.

Congo’s government said at least 7,000 people have died in the fighting since January. At least 600,000 people have been displaced by the fighting since November, according to OCHA.

Several African armies joined the fray in Congo during wars of the 1990s and early 2000s and millions of people died, mainly from hunger and disease triggered by years of conflict and foreign occupation.

More than two decades later, the mechanisms used to end such conflicts — robust U.N. peacekeeping missions and decisive actions such as sanctions and aid cuts — are frayed.