Three United Nations troops were killed and five others were seriously injured on Sunday by an explosion in Mali, underscoring the dangers facing the four-year-old peacekeeping mission in the country.

The forces were escorting a convoy around 7 a.m. along a road connecting the village of Anéfis to the city of Gao in northern Mali when it either hit a mine or triggered an explosive device, according to a statement by the peacekeeping mission, the Multidimensional Integrated Stabilization Mission in Mali, known by its French acronym, Minusma.

“My thoughts are with those who died and were wounded this morning and their families,” said Koen Davidse, a Dutch diplomat who is the United Nations secretary general’s deputy special representative for Mali.

He said the mission had sent a “rapid response force” to the scene to secure the area and to allow the wounded to be cared for.