Rwanda's ally Uganda, unhappy about another rebel group in DR Congo that threatens its security, has also been accused of helping the M23 - with its officers also spotted at Tchanzu. The UN experts say Uganda has also supplied weapons, hosted rebel leaders and allowed cross-border movements of M23 fighters - accusations Kampala denies.

In the capital, Kinshasa, protesters complaining of a lack of international action attacked foreign embassies, including those of the U.S., France and Rwanda.

The M23 militia, funded and directed by Rwanda, said it had seized the city of Goma, terrifying its people, many of whom sought shelter there after fleeing the rebel advance.

An armed group backed by Rwandan troops took control of the airport in the besieged DR Congo city of Goma on Tuesday, a security source said, dealing a major blow to Congolese forces and putting the eastern regional capital on the brink of falling .

Rwandan backed rebels have entered the city of Goma, a key city in neighboring Democratic Republic of Congo. Could the mineral rich region be in danger of tipping into all out regional conflict?

Many Congolese see the rebel advance as an invasion of their country by a foreign power in an attempt to seize land and Congo’s valuable rare minerals.

M23's last occupation of Goma was short-lived, and within a year they were a defeated force. This time, things are different.