Boko Haram leader believed to be among several fighters killed

Several senior Boko Haram fighters have been killed by Nigeria's air force, with the group's leader believed to be among the dead.

The Islamist group's leaders were attacked by government planes inside the Sambisa forest in northeast Nigeria on Friday, the air force said.

Boko Haram kidnapped 219 girls from their secondary school in Chibok in April 2014 and have killed an estimated 15,000 people in their fight to set up an Islamist state.

A video of the alleged missing girls abducted from the northeastern town of Chibok emerged shortly after their abduction.

"Their leader, so called 'Abubakar Shekau', is believed to be fatally wounded on his shoulders," the statement by military spokesman Colonel Sani Kukasheka Usman added, without going into details on the source of its information.

The news emerged on Tuesday, as U.S. Secretary of State John Kerry arrived in the country for talks on tackling the militants.

The Nigerian military has reported the death of Boko Haram's Shekau in the past, only to have a man purporting to be him later appear, apparently unharmed, making video statements.

There was no immediate reaction from the group, which only communicates with the media by videos.

Boko Haram released a video earlier this month appearing to show some of the Chibok schoolgirls kidnapped by the Islamist group.