BAMAKO, Mali (AP) — Two helicopters collided on a moonless night and killed 13 French soldiers fighting Islamic State group-linked extremists in Mali, France said Tuesday, mourning its highest military death toll in nearly four decades. The deaths draw new attention to a worrying front in the global fight against extremism, one in which France and local countries have pleaded for more support. In a surge of violence this month, attackers often linked to IS have killed scores of troops in West Africa’s arid Sahel region and ambushed a convoy of employees of a Canadian mining company, leaving at least 38 dead. French President Emmanuel Macron expressed “deep sadness” after the Monday evening crash. It was France’s highest military toll since 1983, when 58 paratroopers were killed in a truck bombing in Lebanon.