As many as 500 women and children taken from Damasak primary schools . Kidnapped by Nigerian militants as troops advanced on north-eastern town . Official confirms the extremists planned to use them as human shields . Mass grave also discovered in the town , used as an administrative centre .
As many as 500 women and children taken from Damasak primary schools . Kidnapped by Islamic militants as troops advanced on north-eastern town . Official confirms the extremists planned to use them as human shields . Mass grave also discovered in the town , used as an administrative centre .