The United Nations has confirmed the killing of at least one of its peacekeepers while eight others were seriously injured in an attack in northern Mali.

The U.N. Secretary General Antonio Guterres, the Security Council, and the head of the U.N. peacekeeping mission in Mali, all strongly condemned the attack.

Stephane Dujarric, the UN spokesman, confirmed in a statement that the peacekeepers, who came from neighbouring Burkina Faso, were part of a security patrol that was targeted first by an improvised explosive device and then by direct small arms fire seven kilometers from their base in the town of Ber.

The statement added that the peacekeeper killed on Friday was the ninth to die in Mali this year.

The U.N. Secretary-General Antonio Guterres urged Mali’s authorities to immediately identify the attackers and bring them to justice, while emphasizing that attacks against U.N. forces “may constitute war crimes under international law.” Says Dujarric.

While calling for immediate investigation into the incident, the Security Council also emphasized that attacking peacekeepers may not only be a war crime, but that participation in planning, directing, funding, or carrying out such an attack may result in sanctions.

The UN has deployed about 12,000 peacekeepers in northern Mali, to tackle the insurgency in the country with about 300 of them killed so far.

The unrest in the West African country has displaced some six million people and sent hundreds of thousands of others to their graves.