MAIDUGURI, Nigeria, March 14 (Reuters) - Islamist militant sect Boko Haram on Tuesday published a video purporting to show the execution of three men the group accused of being Nigerian military spies.
The seven-minute clip, the first online video of an execution said to be by Boko Haram to be posted in two years, showed three men wearing orange jumpsuits. One is decapitated by masked men while the other two are shot.
The masked men criticise President Muhammadu Buhari and Nigeria's military campaign against the eight-year long insurgency in the north of the country. The militant group has killed more than 15,000 people and forced more than 2 million to flee their homes.
"These are your boys you sent," said one militant in a message aimed directly at Buhari as the men kneel on the ground.
The militant insurgency is aimed at creating a state that adheres to strict Islamic laws in the northeast of Africa's most populous nation.
In December, Buhari said that the group had been pushed out of its last enclave in the northeastern Sambisa forest. Days later, a militant man who identified himself as Boko Haram leader Abubakar Shekau denied the government's assertion.
Shekau did not appear in the latest video, narrated in a mixture of Arabic and the Hausa language spoken widely in northern Nigeria. The video was sent to a number of media houses.
A Nigerian army spokesman challenged the militant group to detail which areas it controlled, but gave no answer when asked if the men were military intelligence officers.
"We are focusing on stabilization and consolidating our counter-terrorism and counter-insurgency operations," army spokesman Sani Usman said in a text message.
"Let them mention that part of Nigerian territory they are holding," he said.
Nigeria has witnessed an increase in attacks or attempted attacks bearing the hallmarks of Boko Haram in crowded areas, such as markets and refugee camps, since the end of the rainy season in late 2016.
Most of the attacks have either been foiled or the suicide bombers have managed only to blow themselves up. (Additional reporting Alexis Akwagyiram; editing by Richard Lough)