GOMA, Congo (AP) — Kenya’s president said Wednesday that his country is sending more than 900 military personnel to eastern Congo to join a new regional force tasked with trying to calm deadly tensions fueled by armed groups.

Kenyan President William Ruto called the mission “necessary and urgent” for regional security, and said he and Congo’s president had agreed on how Kenyan forces would work with Congolese and other forces on disarming rebels and peacekeeping.

The Kenyan forces will be based in Goma, eastern Congo’s largest city. The East African Community regional force, agreed upon by heads of state in June and led by a Kenyan commander, also has two battalions from Uganda, two from Burundi and one from South Sudan.

Late Tuesday, angry crowds set fire to United Nations vehicles in Goma as frustrations mount over the advance of M23 rebels and the deteriorating security situation in the country’s east.

Violence by armed groups has led to a diplomatic crisis between Congo and neighboring Rwanda. Congo has accused Rwanda of supporting the rebels, which Rwanda denies while accusing Congo of backing another rebel group hostile to Rwanda.

The U.N. vehicles were targeted in Goma amid false rumors that the U.N. had transported rebels, adding to the dissatisfaction many people in eastern Congo have with the efforts of a peacekeeping mission known as MONUSCO.

“Because of these rebels, we have fled our homes in Rugari, Kibumba,” protester Kasereka Munyafura said, standing next to the truck on fire. “That is why we are angry, and we have just burnt the vehicles of MONUSCO because it makes us suffer.”

Earlier Tuesday, the U.N. peacekeeping mission announced a “strategic and tactical withdrawal” from embattled Rumangabo. The M23 rebels have been trying to advance on the town, which houses a military base.

The M23 rose to prominence more than a decade ago when its fighters seized Goma, which sits along the border with Rwanda. After a peace deal, many of M23′s fighters were integrated into the national military.

The group reemerged last November, saying the government had failed to live up to its decade-long promises. Over the weekend, the rebels doubled the territory they hold, seizing control of two major towns.