An unknown number of people were killed and several others wounded when United Nations peacekeepers opened fire on a border post in eastern Democratic Republic of Congo (DRC), the UN said. Video of the incident, shared on social media, shows men – at least one in police uniform and another in army uniform – advancing towards the stalled UN convoy behind a closed barrier in Cassidy. The city is located in Beni territory of eastern DRC on the border with Uganda. After a verbal exchange, peacekeepers were seen opening fire before opening the gate, driving and continuing to fire as people scattered or hid. “During this incident, soldiers from the intervention brigade of the MONUSCO force returning from leave opened fire on the border post for unexplained reasons and forced their way through,” the UN mission in Cassidy said in a statement on Sunday. “This serious incident has resulted in loss of life and serious injuries.” The Special Representative of the UN Secretary-General in DR Congo, Bidou Keita, said an investigation had been launched and the suspected perpetrators had been arrested. “In the face of this unspeakable and irresponsible behavior, the perpetrators of the shooting were identified and arrested pending the results of the investigation, which has already begun in cooperation with the Congolese authorities,” he said. He added that contact had been made with the soldiers’ country of origin so that legal procedures could be urgently initiated. He did not name the country. Meanwhile, UN chief Antonio Guterres said he was “outraged” by the incident and called for “accountability”. Guterres was “saddened and disappointed” to learn of the shootings by members of the peacekeeping unit, a UN statement said. Barthelemy Kambale Siva, a spokesman for the North Kivu governor in Kasidi, said earlier that “eight people, including two police officers working at the dam, were seriously injured” in the incident. Shiva, speaking to the AFP news agency, did not say why the UN convoy was prevented from crossing the barrier. There are more than 120 armed groups operating in the troubled east of the DRC. The UN first deployed an observer mission to the region in 1999. In 2010, it became the peacekeeping mission MONUSCO – the United Nations Stabilization Mission in the Democratic Republic of the Congo – with a mandate to conduct offensive operations. Among them there were 230 deaths, according to the UN. Last week, deadly demonstrations demanding the withdrawal of the United Nations took place in several cities in eastern DRC. A total of 19 people, including three peacekeepers, were killed. Anger has been fueled by perceptions that MONUSCO is unable to do enough to stop attacks by armed groups. UN Under-Secretary-General for Peacekeeping Operations Jean-Pierre Lacroix was in the central African country on Saturday to “talk to the Congolese authorities,” he said. “[They would] to consider ways in which we can both avoid a repeat of these tragic incidents and, above all, work better together to achieve our goals,” he said. “We hope that the conditions will be met, in particular the return of state authority, so that MONUSCO can complete its mission as soon as possible – and leave room for other forms of international support.”