UNITED NATIONS (AP) — The U.N. Security Council and the secretary-general on Monday strongly condemned the killing of a U.N. peacekeeper in the Central African Republic during an attack by members of the mainly Christian anti-Balaka group.

The U.N. peacekeeping mission in the country said the peacekeeper from Burundi was killed on Sunday when troops were trying to stop an attack in Grimari in the center of the country that began when anti-Balaka fighters under the command of Dimitri Ayoloma opened fire on the homes of the mayor and a regional official.

The mission said U.N. peacekeepers in Grimari, in Ouaka province, immediately intervened trying to end the assault, and the rebels deliberately opened fire against them, fatally injuring the soldier from Burundi.

Mankeur Ndiaye, who heads the peacekeeping mission, condemned the “heinous act” that cost his life.

“This attack on the city of Grimari and the peacekeepers is unacceptable and constitutes a serious crime under the jurisdiction of national and international courts,” he said.

The Security Council, Secretary-General Antonio Guterres and Ndiaye all stressed that any attack on a U.N. peacekeeper may constitute a war crime.

The mineral-rich Central African Republic has faced deadly inter-religious and inter-communal fighting since 2013, when predominantly Muslim Seleka rebels seized power in the capital, Bangui. Mostly Christian anti-Balaka militias fought back, resulting in the killing of thousands and the displacement of thousands more.

The country saw a period of relative peace in late 2015 and 2016, but violence intensified and spread afterward. In February 2019, the government signed a peace agreement with 14 armed groups, but some armed groups did not sign and since then there have been intermittent serious incidents.

Secretary-General Guterres also strongly condemned a separate attack by two suspected rebel groups against a U.N. patrol on the Ndele-Birao axis in northern Bamingui-Bangoran province on Sunday that injured a Pakistani peacekeeper, U.N. spokesman Stephane Dujarric said.

The U.N. Mission said civilians found the bullet-ridden body of a U.N. peacekeeper from the U.N. mission in Ndele in the same province on March 7. The peacekeeper had reportedly been killed by fighters from the Popular Front for the Renaissance in the Central African Republic (FPRC), an ex-Seleka faction, the mission said.

The Security Council strongly condemned that killing.