Jihadists in northeast Nigeria have released a video showing the execution of two soldiers and a policeman, posted online late Monday by the Islamic State group (IS) propaganda agency Amaq.
The video, dated Sunday, was made by a branch of Boko Haram that has sworn allegiance to IS known as the Islamic State Group in West Africa (ISWAP).
Its release came days after the militants announced the kidnapping of 14 people including two aid workers and, according to the jihadists, six members of the security forces.
It shows three men in plain clothes kneeling in a field, introducing themselves as members of the Nigerian security forces before masked men in fatigues open fire on them shouting "Allahu Akbar" (God is greatest).
"We tell the Nigerian army that we will never spare those fighting against the people who follow Allah's religion," one of the executioners said in Hausa, a language widely spoken in the north of the country.
"We will attack your bases and confront you on your routes," the militant added, shortly before the execution.
One of the three victims introduced himself as a police sergeant, saying the jihadists had "captured" him when he was on his way to Maiduguri, the capital of Nigeria's northeastern Borno state.
Those abducted last Wednesday included two Red Cross workers.
ISWAP claimed responsibility for the kidnapping, saying six members of the Nigerian security forces were among the hostages.
The group was taken on the highway outside Maiduguri at a fake security checkpoint set up by the militants disguised as Nigerian soldiers.
ISWAP focuses on military targets, while Boko Haram mainly attacks civilians.
The splinter group has released several grisly execution videos of security personnel, with the victims dressed in orange jumpsuits mimicking IS-style executions.
The decade-long insurgency in Nigeria has claimed some 35,000 lives and displaced about two million from their homes in the northeast of the West African country.