Nigeria's military has announced a reprieve for 66 soldiers who had been sentenced to death for refusing to fight Boko Haram.

The soldiers, who were to be killed by a firing squad, will each serve 10 years in prison.

They were convicted by court martial over their refusal to drive down a road at night after dozens of colleagues died in a Boko Haram ambush.

The sentences were commuted following a review of court martials.

The review was ordered by General Tukur Buratai, the country's army chief of staff.

Nearly 600 other cases are also being considered.

Hundreds of Nigerian soldiers have deserted their posts, complaining that they are not properly equipped to fight Boko Haram, a terror group which has allied itself with the Islamic State group.

The group has been waging an insurgency since 2009 and is seeking to create an Islamist state in north-eastern Nigeria. It is responsible for the deaths of about 20,000 people.

The reprieves come as a former presidential adviser on national security is on trial for allegedly diverting $2.1bn meant to buy weapons for the military.

The review of the soldiers' cases is part of a wider investigation ordered by President Muhammadu Buhari into the military and corruption.

President Buhari won the country's March general election after pledging to destroy Boko Haram and to rescue more than 200 schoolgirls kidnapped by the extremists.