Chad: The soldiers getting ready to fight terror in Africa
Hundreds of soldiers from Chad and Niger are crossing the border into Nigeria to fight Boko Haram.
It is the first incursion deep into Nigeria and is part of a growing involvement of Nigeria's neighbours, who themselves have come under attack.
Thomas Fessy reports from Chad, where he followed American special forces and Nato allies training regional army units as part of "Operation Flintlock".
- From the section Africa