The United Nations on Sunday told its staff not to go to the airport and to shelter in place, according to an internal email seen by AP.

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 last year acknowledged 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 estimate there are up to 4,000 Rwandan forces in Congo.

Members of the United Nations Organization Stabilization Mission in the Democratic Republic of the Congo (MONUSCO) ride on a pickup truck as they secure the evacuation of non-essential UN staff, following the fight between M23 rebels and the Armed Forces of the Democratic Republic of the Congo, in Goma, North Kivu province, Democratic Republic of Congo, on Jan. 25, 2025. (Reuters/Arlette Bashizi TPX IMAGES OF THE DAY)

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

Rwanda’s Foreign Minister Olivier Nduhungirehe told AP on Sunday that the decision to cut ties was a unilateral move by Congo “that was even published on social media before being sent to our embassy.”

“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,” he said.

In the last 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 António Guterres’ spokesman said Sunday ahead of an emergency meeting of the U.N. 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 Stéphane Dujarric said.

On Sunday morning, heavy gunfire resonated across Goma, just a few miles from the front line. Scores of displaced children and adults fled the Kanyaruchinya camp, one of the largest in eastern Congo, right near the Rwandan border, and headed south to Goma.

“We are fleeing because we saw soldiers on the border with Rwanda throwing bombs and shooting,” said Safi Shangwe, who was heading to Goma.

“We are tired and we are afraid, our children are at risk of starving,” she added.

Internally displaced civilians from the camps in Munigi and Kibati carry their belongings as they flee following the fight between M23 rebels and the Armed Forces of the Democratic Republic of the Congo, in Goma, eastern Democratic Republic of Congo, on Jan. 26, 2025. (Reuters/Aubin Mukoni)

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

“We are going to Goma, but I heard that there are bombs in Goma, too, so now we don’t know where to go,” said Adèle Shimiye.

Hundreds of people attempted to flee to Rwanda through the “Great Barrier” border crossing east of Goma on Sunday. Migration officers carefully checked travel documents.

“I am crossing to the other side to see if we will have a place of refuge because for the moment, security in the city is not guaranteed,” Muahadi Amani, a resident of Goma, told the AP.

Earlier in the week, the rebels seized Sake, 16 miles from Goma, as concerns mounted that the city could soon fall.

Congo’s army said Saturday it fended off an M23 offensive with the help of allied forces, including U.N. troops and soldiers from the Southern African Development Community Mission, also known as SAMIDRC.

In addition to the two South African peacekeepers, seven South African troops with SAMIDIRC have been killed in recent days, South Africa’s Ministry of Defense said.

Since 2021, Congo’s government and allied forces, including SAMIDRC and U.N. troops, have been keeping M23 away from Goma. The U.N. peacekeeping force entered Congo more than two decades ago and has around 14,000 peacekeepers on the ground.