The Nigerian army has said the leader of the Boko Haram militant group, Abubakar Shekau, has been "fatally wounded" in a raid.

In a statement, it said its planes had attacked the group inside the Sambisa forest in the country's northeast on Friday. A number of senior figures within the group have also been killed. However, Nigeria has claimed they killed him three times in the past, only for him to later resurface in video and audio recordings. The statement comes as US Secretary of State John Kerry is visiting the country to discuss Islamic extremism and regional security.

"The fact is that through the multi-national joint task force with the help from the United States, France and the United Kingdom, Nigeria and its neighbours are steadily degrading Boko Haram's capabilities. Your country has taken back most of the territory that the terrorists had once captured and Cameroon, Niger and Chad and Benin have made important contributions and enormous sacrifices in areas along Nigeria's borders," he said.