The Nigerian army is investigating allegations that soldiers tied up and killed a suspected Islamist militant before burying him in a shallow grave.
A video showing men dressed in army fatigues torturing and killing the victim was widely circulated on messaging apps over the weekend.
It is not clear when the footage dates from.
But the army says it was probably filmed in the north-east, where jihadists have been fighting for years.
An army spokesman described the violence shown in the video as a "dastardly act" that was against the core values of the Nigerian army.
Correspondents say the Nigerian authorities usually dismiss allegations of human rights abuses in the conflict against the Islamist militant group Boko Haram.
But in this case the Nigerian army issued a strong statement of condemnation and promised the perpetrators would be tried and punished.
The military has also been under scrutiny for recent allegations that it detained thousands of children for suspected links to Boko Haram.
It has denied those reports, saying it treats children as "victims of war and not as suspects".
Nigeria's armed forces have been fighting Boko Haram in the north-east for the past decade.
The authorities have said the group is "technically" defeated but it continues to attack military and civilian targets on a regular basis.
Latest Stories
-
Have capacity to influence policy – former MiDA boss to engineers
7 mins -
Silva to leave Chelsea at end of season
10 mins -
Ghana’s Online Freedom of Expression in peril, citizens’ rights eroded – Londa Report
14 mins -
CAF Confed Cup: Karim Zito blames semi-final exit on lack of experience
19 mins -
CAFCC: Dreams FC didn’t lose because of stage fright – Karim Zito
26 mins -
ECG threatens to disconnect Ashanti Regional Minister’s residence if found to be in debt
37 mins -
Gladys Bosco sings about hope in ‘Me Ewurade Bra’
45 mins -
Accra High Court refuses requests to compel Akufo-Addo to receive anti-LGBTQ+ bill
56 mins -
I almost took my life – Fella Makafui
1 hour -
The emergence of the future: Prof. Jane Naana Opoku Agyemang
1 hour -
Knowing when to mute the mic: Kwasi Kwarteng’s choking example on ‘Blue and White’
1 hour -
R. Kelly’s sex abuse conviction in Chicago upheld in appeals court
2 hours -
Azumah Nelson returns to the ring to face EU Ambassador in a match to empower youth
2 hours -
UEFA U-16 Tournament: Black Starlets come from behind to beat Kazakhstan 5-1 in final game
2 hours -
Every worker in Ghana must be concerned about ILO’s report on SSNIT – GNAT President
2 hours