Defence Chief Alex Badeh reportedly told News Agency of Nigeria that "the good news for the parents of the girls is that we know where they are," while adding the army could not go for rescue because "we cannot kill our girls in the name of trying to get them back."
More than 200 girls of the Chibok community in Borno state in northeastern Nigeria were abducted on April 14.
The Islamist militant group Boko Haram claimed responsibility for the mass kidnapping and threatened to sell the girls. They even said that if their demands were not met they would forcefully marry the girls.
People including celebrities around the world have showed their support for the girls by taking part in protests and joining online campaigns on social networking sites calling for their rescue.