Shugaban Najeriya MUhammadu Buhari, ya kai wata ziyara jihar Borno da ke yankin Arewa maso Gabashin kasar mai fama da hare-haren 'yan ta'adda. Sai dai bai ziyarci gari Auno ba, inda aka kashe mutane sama da 30 a wani harin ta'addanci a farkon wannan makon.