Nigeria has sentenced 54 soldiers to death by firing squad for mutiny while fighting against insurgents in the northeast, their lawyer said on Thursday.

Another five were acquitted and discharged in the secret trial, lawyer Femi Falana said.

They were the first batch of 97 soldiers being court martialed for offences including mutiny, assault, absconding, house breaking and disorderly behavior.

Low morale, partly linked to a dearth of adequate equipment and weapons in the face of a determined Boko Haram Islamist insurgency, has led to a series of desertions in the northeast and at least one mutiny. 

Troops have also been repeatedly accused by human rights groups of abuses including killing civilians and torching their homes, charges the leadership usually denies.