GOMA, Congo — Residents in eastern Congo's largest city, Goma, were fleeing on Monday after Rwanda-backed rebels claimed to have captured the regional hub from Congolese forces as fighting escalated despite calls from the U.N. Security Council for the insurgents to withdraw.

Gunshots rang out across Goma overnight before dozens of rebels in military uniform early Monday morning marched into the capital of North Kivu province, which sits on the border with Rwanda in the volatile region rich in minerals critical to much of the world's technology.

The Congolese government confirmed the presence of M23 rebels in Goma, 930 miles east of capital Kinshasa, but stopped short of saying they were in control of the city. In a statement on X, government spokesman Patrick Muyaya asked Goma residents to stay at home and also urged Congolese nationals around the world to mobilize in support of the country. "No centimeter will be given up!!!" Muyaya wrote.

As the rebels entered Goma, a fire at the city's Munzenze prison on Monday morning resulted in the escape of thousands of inmates. "All the prisoners who were detained came out, whether women, men or minors, everyone came out," said Mwamisyo Ndungo, one of the escapees who estimated that more than 2,000 fled the facility.

The M23 rebels are one of about 100 armed groups vying for a foothold in the mineral-rich region in the decades-long conflict, one of Africa's largest. The rebels temporarily took over Goma in 2012, before they were forced to pull out under international pressure, and resurfaced in late 2021, with increasing support from Rwanda, according to Congo's government and United Nations experts. Rwanda has denied such support.

Rwanda's Ministry of Foreign Affairs accused Congo of failing to enter a dialogue with M23, which it described as a "Congolese rebel group fighting to protect their community." That failure, it said, has prolonged the fighting that continues to present "a serious threat to Rwanda's security and territorial integrity, and necessitates Rwanda's sustained defensive posture."

The advance into Goma is the culmination of a prolonged battle between the rebels and the Congolese security forces that saw several towns along the Rwandan border falling to the insurgents.

Analysts have warned the latest escalation could further destabilize the region, which is already home to one of the world's largest humanitarian crises with more than 6 million people displaced, including more than a third of North Kivu's population.

A regional hub for trade, security and humanitarian efforts, Goma's airport, which is key for transporting supplies, has been shut following the fighting.

Rwanda's state television also showed several Congolese soldiers surrendering in the Rwandan town of Rubavu after crossing the border from Goma.

After its emergency meeting late Sunday, the U.N. Security Council issued a statement calling on the M23 to immediately reverse its advances. Other countries including the United States, United Kingdom and France have also condemned the rebel push.

“The members of the Security Council condemned the ongoing flagrant disregard for the sovereignty and territorial integrity of the DRC,” the U.N. statement added, referring to Congo's formal name, the Democratic Republic of Congo.