Can France defeat armed groups in the Sahel? Niger has struggled to cope with years of attacks by armed groups. They've killed thousands. Areas around the capital Niamey were largely considered secure. But on Sunday, gunmen on motorbikes targeted a wildlife sanctuary a short drive from the city. Six French humanitarian aid workers were shot dead, along with their Nigerien driver French prosecutors say a 'terror investigation' is under way. And President Emmanuel Macron chaired a national defence council meeting to consider further action. So, how big a threat are the fighters with an Islamic agenda in west Africa? - Subscribe to our channel: aje.io/AJSubscribe - Follow us on Twitter: twitter.com/AJEnglish - Find us on Facebook: www.facebook.com/aljazeera - Check our website: www.aljazeera.com/