MAO, Chad - Under the glare of the Saharan sun, a US special forces trainer corrects the aim of a Chadian soldier as he takes cover behind a Toyota pick-up and fires at a target with his AK47 -- a drill that could soon save his life.Chad is sending hundreds of troops to fight Boko Haram in neighboring Nigeria as part of a regional offensive against the Islamist group, which killed an estimated 10,000 people last year in a campaign to carve an Islamic emirate from the north of Africa's largest oil producer.At the end of the exercise, a US trainer shows the 85 Chadians the paper target peppered with bullet holes - many of them outside the drawing of a gunman. "Not so great," he says and orders them to do a round of push-ups -- in which American, Italian and Belgian trainers all take part, laughing.The annual 'Flintlock' counter-terrorism exercises are a decade-old US-sponsored initiative to bolster African nations' ability to fight militant groups operating in the vast ungoverned spaces of the Sahara with training."Even before the conflict with Boko Haram, we were preparing to face a group like them," said the commander of the Chadian troops, Captain Zakaria Magada, whose Special Anti-Terrorist Group (SATG) is equipped and trained by the United States."Boko Haram is just a militia of civilians. We are an organized army. They cannot face up to us."