ABIDJAN (Reuters) - Three United Nations soldiers from Chad were killed and two others wounded by an explosive device as they were escorting a convoy in northern Mali on Thursday, the peacekeeping mission in the West African nation said.  More than 80 members of the UN mission, known as MINUSMA, have been killed since 2013 in attacks by militant groups active in the country s north and center, making it the world s deadliest peacekeeping operation.  The mission said in a statement that the peacekeepers  vehicle struck the explosive device between the northern towns of Tessalit and Aguelhok around 2:30 p.m. (1430 GMT).  MINUSMA spokesman Olivier Salgado later told Radio France Internationale that the soldiers involved were from Chad, which has one of the region s most effective armies.  I condemn with the greatest energy such abject acts, whose only objective is to destabilize the country and harm the peace process under way in Mali,  said interim mission chief Koen Davidse. The rise of jihadist groups - some linked to al Qaeda and Islamic State - in the arid Sahel has alarmed Western powers like France, which has deployed thousands of troops to the region in response.  Four U.S. Special Forces troops were killed earlier this month in neighbouring Niger by fighters believed to belong to a local Islamic State affiliate operating out of Mali. Militants have exploited porous borders - particularly between Mali, Niger and Burkina Faso - to step up attacks on military and civilian targets, including tourist sites in regional capitals. The G5 Sahel, an anti-terrorism taskforce of soldiers from those three countries, as well as Chad and Mauritania, plans to launch its first joint operations in the coming days.    
Explosion kills three Chadian U.N. peacekeepers in northern Mali