LANRE OLA A joint military force from Nigeria, Niger and Cameroon said it had killed more than 100 Islamist insurgents, including 10 commanders, in the past few weeks, as it intensifies a ground and air offensive in the Lake Chad region. Boko Haram fighters and its splinter Islamic State West Africa Province (ISWAP) group have for more than a decade battled the Nigerian army in a conflict that has sucked in neighbouring states. Multinational Joint Task Force spokesman Colonel Muhammad Dole said troops had ventured deep into enclaves controlled by insurgents in the Lake Chad area and recovered several weapons,…