The Alpha jet lost radar contact on Wednesday while on a mission to support troops battling jihadists in the northeastern Borno state. The air force said it believed the jet with two crew may have crashed.

Boko Haram on Friday released a video showing a militant standing on what the group claimed was the wrecked fuselage of the plane with the Nigeria Air Force number 475.

"It is obvious that the Boko Haram Sect, in its characteristic manner of employing false propaganda, is seeking to claim credit for what was obviously an air accident," the air force said in a statement.

It said investigations into how the aircraft crashed were still ongoing. On Friday it had said the whereabouts of the two crew was still unknown.

In 2014, Boko Haram said it shot down a Nigerian air force jet and showed a video claiming to have beheaded its pilot.

Since the Islamist insurgency broke out in 2009, Nigeria's conflict has killed around 36,000 people in the region and displaced some two million from their homes.