GOMA, Congo — Congolese rebels and allied Rwandan forces entered the outskirts of Goma on Sunday and the airport in the key eastern city was no longer in use, the top U.N. official in the country said. Thousands fled the fighting that also killed at least 13 peacekeepers.

The M23 rebel group has made significant territorial gains along the border with Rwanda in recent weeks, closing in on Goma, the provincial capital of around 2 million people and a regional hub for security and humanitarian efforts.

The U.N. special representative for Congo, Bintu Keita, told an emergency meeting of the U.N. Security Council on Sunday that despite the support of international peacekeepers for the Congolese armed forces, M23 and Rwandan forces penetrated the Munigi quarter on the outskirts of Goma, “causing mass panic and flight amongst the population.” Munigi is 5 miles from Goma.

Keita said M23 fighters were advancing “in a context of permanent movement of populations fleeing for their lives or used as human shields.”

“Roads are blocked and the airport can no longer be used for evacuation or humanitarian efforts. M23 has declared the airspace over Goma closed. In other words, we are trapped.” She said the U.N. is temporarily relocating nonessential personnel from Goma.

In the past 48 hours, two U.N. peacekeepers from South Africa and one from Uruguay were killed, and 11 peacekeepers were injured and hospitalized, U.N. Secretary-General Antonio Guterres’ spokesman said Sunday ahead of the emergency meeting of the Security Council.

The U.N. chief reiterated his “strongest condemnation” of the M23 offensive “with the support of the Rwanda Defense Forces” and called on the rebel group to immediately halt all hostile action and withdraw its forces, U.N. spokesman Stephane Dujarric said.

Congo, the United States and U.N. experts accuse Rwanda of backing M23, which is mainly made up of ethnic Tutsis who broke away from the Congolese army more than a decade ago.

It’s one of about 100 armed groups that have been vying for a foothold in the mineral-rich region, where a long-running conflict has created one of the world’s largest humanitarian crises.

Rwanda’s government denies backing the rebels, but it acknowledged last year that it has troops and missile systems in eastern Congo to safeguard its security, pointing to a buildup of Congolese forces near the border. U.N. experts say there are up to 4,000 Rwandan forces in Congo.

During Sunday’s meeting of the U.N. Security Council, Rwanda’s U.N. Ambassador Ernest Rwamucyo blamed Congo’s government, saying the current crisis could have been averted if it had “demonstrated a genuine commitment to peace.”

Rwamucyo said Rwanda strongly believes there is no military solution and ways have to be found to return to diplomatic and political processes.

The Congolese Foreign Ministry said late Saturday that it was severing diplomatic ties with Rwanda and pulling out all diplomatic staff from the country “with immediate effect.”

The decision to cut ties was a unilateral move by Congo “that was even published on social media before being sent to our embassy,” Rwandan Foreign Minister Olivier Nduhungirehe told The Associated Press on Sunday.

“For us, we took appropriate measures to evacuate our remaining diplomat in Kinshasa, who was under permanent threat by Congolese officials. And this was achieved on Friday, one day before the publication of this so-called note verbale on social media.”

On Sunday morning, heavy gunfire resonated across Goma, just a few miles from the front line.

Some of the displaced worried that they will not be safe in Goma either.

Since 2021, Congo’s government and allied forces, including around 14,000 U.N. peacekeepers, have been keeping M23 away from Goma.