The rebel group M23 launched an offensive against the city of Goma on Monday, after extending and then rescinding an offer to negotiate with the government of the Democratic Republic of the Congo, or DRC.

A takeover of this capital of the North Kivu province would be a major victory for the insurgency, which aims to depose the central government in Kinshasa and could easily provoke a regional conflict. The DRC and surrounding countries have already been devastated by multiple wars in recent decades.

On Saturday, M23 rebels captured the town of Kibumba. On Sunday, they moved south toward Goma, a city of 1 million that is close to the DRC’s eastern border with Rwanda. Thousands fled their homes as the insurgency advanced.

On Monday morning, M23 leaders announced that they would stop their offensive if the government would agree to talks and demilitarize Goma. But government spokesman Lambert Mende refused to give in to this “blackmail,” according to the Associated Press.

M23 spokesman Col. Vianney Kazamara then said that the insurgency would proceed. "The army provoked us. They have fired on our men. ... We are going to take Goma tonight.”

M23 was officially formed earlier this year when DRC soldiers defected to mount an insurgency. But the group can trace its roots back much farther; many of its members were linked to the National Congress for the Defense of the People, or CNDP, another Congolese rebel organization founded in 2006.

That group made its own advance on Goma three years ago; it was close to seizing the city when the DRC government agreed to negotiate with the insurgents. According to the resulting March 23, 2009, agreement, which would give the M23 its name, many of the rebels were absorbed into the official military.

This year’s repeat defection makes it clear that little has changed since 2009.

Like the CNDP, M23 is widely believed to be supported by Rwanda. An October report for the U.N. Security Council suggested that Rwanda’s very own Defense Minister General James Kabarebe was directly involved in M23’s operations, but the U.N. itself has not confirmed these allegations.

Rwanda, whose rivalry with the DRC government stems from the fallout of its own devastating civil war and genocide of the 1990s, denies working with the M23 rebels. But the U.N. points out that the insurgency seems too well-organized and too well-armed to be working independently.

For months, the M23 has wrought havoc in the eastern DRC. Its members have been charged with committing frequent and horrific atrocities against civilians, including rapes, pillaging, summary executions, child recruitment and abduction. Gen. Bosco Ntaganda, one of the M23’s leaders, is wanted for war crimes by the International Criminal Court. Another leader, Sultani Makenga, has been placed under an asset freeze and travel ban by both the U.N. and the United States.

But the DRC has been unable to suppress this deadly insurgency. The national army is in shambles; troops often have to go without shelter and other basic accommodations. Corruption in the ranks often delays payments. Soldiers have complained about being sent into battle on an empty stomach, wielding inadequate weaponry and lacking a pair of boots.

Moreover, the DRC suffers a dire lack of infrastructure; much of the population lives in poverty, despite an abundance of natural resources and minerals. The country is still struggling to recover from two devastating wars that led to the death of about 5 million people between 1996 and 2003.

The United Nations has had a peacekeeping presence in the DRC for about a decade. That organization, called the United Nations Organization Stabilization Mission in the Democratic Republic of the Congo, or Munesco, has more than 20,000 military and civilian personnel on the ground. This weekend, U.N. helicopters were deployed against the rebel advance into Kibumba but failed to stop M23 from seizing the town and moving on toward Goma.

The clashes that erupted at the edges of the provincial capital on Monday afternoon pit M23 against the DRC army and U.N. peacekeepers once again. U.N. spokesperson Kieran Dwyer told the Associated Press on Sunday that 17 “quick reaction units” had been sent to the city, but the outcome is far from certain.

"The situation in Goma is extremely tense," he said, according to the AP. "There is a real threat that the city could fall into the M23's hands and/or be seriously destabilized as a result of the fighting.”