Boko Haram / Credit: AFP

Boko Haram militant group leader Alhaji Modu, alias Bem Bem, was killed last week in an air strike, the Nigerian military announced on Sunday.

It said 28 militants were also killed in the airstrike carried out on 3 August in the north-western Borno State.

The BBC has not been able to independently verify the report.

Modu is alleged to have coordinated Boko Haram attacks in Nigeria, Niger, and Cameroon from caves in the Mandara mountains.

Zagazola Makama, a counter-insurgency expert quoted by various local media, says Modu was an armed robber before becoming a Boko Haram commander.

The Nigerian government says that the military has recorded significant success in the fight against Islamist militants, including the voluntary surrender of thousands of militants in the northeast.