OUAGADOUGOU, Burkina Faso (AP) — A U.N. peacekeeper was killed in Mali and others injured in separate attacks in the north of the country, Stephane Dujarric, spokesman for the United Nations secretary-general, said in a statement.

A bomb hit a U.N. vehicle in the Kidal region killing one Egyptian peacekeeper and seriously injuring another on Thursday.

In a separate attack in Timbuktu, gunshots fired toward the U.N. camp injured one peacekeeper from Burkina Faso, said the statement. Dujarric said attacks targeting peacekeepers could amount to “war crimes” and called on Mali's authorities to urgently bring the perpetrators to justice.

The attacks by suspected Islamic extremists come just days after 12 civilians and at least 11 soldiers from the army were killed in the center of Mali, said the statement.

The U.N. peacekeeping mission has been in Mali since 2013, after Islamic extremists took control of major towns in the north. A French-led military operation dislodged the rebels, but the jihadists have since regrouped in rural areas and expanded their reach, targeting Mali's army and the U.N. mission. According to the U.N., 220 peacekeepers have died in Mali.

The jihadist threat is compounded by Mali's current political upheaval. In August, President Ibrahim Boubacar Keita was ousted from power by a military junta. Under international pressure, the junta appointed a civilian-led government to lead the country through an 18-month transition period to new elections. Last week the administration helped to secure the release of four hostages, including Malian politician Soumaila Cisse and three westerners, in exchange for the release of nearly 200 jailed jihadists.

The attacks this week highlight Mali's fragile security, says an expert.

“These attacks sow more mistrust between the public and the government, further eroding confidence after the release of convicted militants who’ve rejoined the battlegrounds,” said Laith Alkhouri, an intelligence specialist who researches violent extremists in West Africa.