A fourth United Nations soldier has died from injuries from a highway bomb in northern Mali, a day after the blast claimed the lives of three of his comrades, a spokesman for the UN peacekeeping mission said Tuesday. Their vehicle struck an improvised explosive device (IED) during a search for mines in Tessalit, in the deeply troubled Kidal region. Two other peacekeepers were seriously injured, the MINUSMA mission said. UN chief Antonio Guterres, in a statement issued in New York, strongly condemned the blast and warned that attacks on peacekeepers could constitute war crimes under international law. The peacekeepers were part of MINUSMA’s Chadian contingent, an official at the mission’s camp in Kidal said on condition of anonymity. MINUSMA — the United Nations Multidimensional Integrated Stabilisation Mission in Mali — was launched in 2013 to help one of the world’s poorest countries cope with a bloody jihadist campaign. It is one of the UN’s biggest peacekeeping operations, with 17,612 troops, police, civilians and volunteers deployed as of May, according to the mission’s website. In total, 181 of its members have been killed in hostile acts, one of the highest tolls in the history of “blue helmet” operations. Seventy-six of the fatalities have been inflicted through IEDs.