Shugaban kasar Najeriya Muhammadu Buhari ya ce al’amarin canjin yanayi shi ne asalin dukkannin tashe-tashen hankula a yankunan Afurka, ya yi kuma kira na musamman kan yaki da cin hanci da rasahawa a lokacin da ya halarci babban taron Aswan da aka yi a kasar Masar.