Nigeria's military says eight soldiers were killed and 17 wounded in two attacks by Islamic extremists in northeastern Nigeria, the Associated Press reports.

The attacks, announced Monday, September 26, bring the official toll to 10 troops killed and 24 wounded this past week in a resurgence of violence after a lull as the extremists confront a leadership struggle.

Also, longtime Boko Haram leader Abubakar Shekau appeared in a video denying Nigerian military reports that he was fatally wounded last month.

Shekau taunts parents of the kidnapped Chibok schoolgirls saying they will only see their daughters if the government swaps them for detained extremist leaders. Shekau warns the people of Chibok that "you have not seen the worst yet."

Nearly 300 girls were kidnapped in April 2014 from a school in the northeastern town, 217 remain missing.