Boko Haram fighters fleeing an attack on their base last week may have used some of the girls kidnapped in 2014 from northeast Nigeria's Chibok as human shields to prevent being fired upon by fighter jets, a military commander said on Wednesday.

Maj. Gen. Lucky Irabor, theater commander of Nigeria's military campaign against the group, showed a news conference aerial footage he said was filmed during the operation in the Sambisa forest that showed Boko Haram fighters moving with women and children.

"The haggard fighters were just using them as a shield," Irabor told reporters in the northeastern city of Maiduguri. "That is why we did not engage them from the air.