Nigeria’s army says it has killed several commanders of the Islamist group Boko Haram in an air strike and seriously wounded its disputed leader.

An army spokesman told the BBC’s Hausa service that Abubakar Shekau’s shoulder was badly injured in the strike on Friday in north-eastern Borno state.

There has been no independent confirmation of the strike.

Claims by the army that it has killed Shekau have turned out to be false on previous occasions.

Boko Haram is fighting to overthrow Nigeria’s government and establish an Islamic State in the north.