Zinder - Aboubacar, usually a worker for a non-governmental organisation, has now taken on another, more ominous role: watching out for suicide bombers.
"We watch everyone," he said in Niger's second-largest city of Zinder. "Last Thursday, a man in a turban whom we had never seen before came to the mosque. We asked him to leave."
His fears reflect the shifting threat of Islamist extremist group Boko Haram, which has in recent weeks carried out attacks across the border from its base in north-eastern Nigeria as regional forces pursue them.