Three peacekeepers from Senegal were killed and five seriously injured after their convoy was hit by an improvised explosive device in central Mali, the UN peacekeeping mission in the country and Senegal’s army said late Tuesday.

Mali is struggling to stem an Islamist insurgency that took root after a 2012 coup and has since spread from the West African country’s arid north.

Thousands have died and millions have been displaced across the Sahel region.

Tuesday’s incident took place near the village of Songobia, 29 km (18 miles) southwest of the town of Bandiagara in Mali’s Mopti region, the UN peacekeeping mission MINUSMA said in a statement.

Senegal’s army also issued a statement saying the victims were part of a Senegalese contingent of the UN mission.

At least 168 peacekeepers have been killed in Mali since the start of the mission in 2013, making it the deadliest UN peacekeeping effort in the world.

“This is another tragic illustration of the complexity of our operational environment and the sacrifices made by the international community for peace in Mali,” said MINUSMA Head of Mission El-Ghassim Wane.