In a statement posted on Facebook on Saturday, the army dismissed as “outlandish and unverified” the witness statements that soldiers had left their posts the day before Monday’s attack.
The army also says no attack even occurred on that day.
Amnesty on Friday published satellite imagery it said showed “hundreds of burned structures” after fighters on motorcycles drove into the town and set homes on fire.
The army statement calls the Amnesty report “another futile effort” to portray the military as incapable.
An extremist resurgence poses a serious challenge for President Muhammadu Buhari as he seeks re-election in two weeks’ time.