The statement did not explicitly say whether the Nigerian army considered the man in the video to be Shekau.
Expert says presence of US and other troops in Maiduguri could trigger attacks in the area, adding to the already very high security risk
Buhari orders high profile arrests after report shows billions wired to ghost firms aided Boko Haram rampage
Former powerful national security advisor Sambo Dasuki among those fighting to save themselves following presidential probe's interim findings.
Nigeria conducts 1,488 airstrikes against Boko Haram over 2 months; in Abuja Senate confirms Buhari’s cabinet picks
The president has been criticised for being slow to name his cabinet since his victory in March elections.
The air force said in a statement after the ceremony it had deployed additional firepower to the northeast.
Parting shot: Nigerian military weak, a tool of politicians and influenced by foreigners, sacked army chief says
Soldiers were poorly equipped and unmotivated to fight Boko Haram, with vital information leaked, Alex Badeh says in withering assessment
Nigerian army has led a series of raids against the jihadists in recent months, succeeding in freeing several dozen women and children.
The spike in violence has sparked concern that gains made by the armies of Nigeria, Niger, Chad and Cameroon since February are being eroded.