At least 15 people were killed and dozens of others injured during two days of demonstrations in Congo’s east against the United Nations mission in the country, officials said Tuesday.

The United Nations said one peacekeeper from Morocco and two international policemen from India serving with the U.N. peacekeeping force were slain and a policeman from Egypt was injured at the U.N. base in Butembo in North Kivu province when “violent attackers snatched weapons from Congolese police” and fired on U.N. personnel.

U.N. Secretary-General Antonio Guterres strongly condemned the Butembo attack and violence targeting multiple U.N. bases across North Kivu since Monday, U.N. deputy spokesman Farhan Haq said.

Haq said that on Tuesday “hundreds of assailants” attacked bases of the U.N. force in Goma and other parts of North Kivu, “fueled by hostile remarks and threats made by individuals and groups against the U.N., particularly on social media.’