Nigeria’s Army Chief Lieutenant General Ibrahim Attahiru among 11 people were killed in a plane crash on Friday.

The plane crashed near Kaduna airport and that it was investigating the cause, the air force said in a statement.

The presidency said the army general and other military officers died in the crash on Friday.

President Muhammadu Buhari, in a presidency statement, described the crash as a “mortal blow … at a time our armed forces are poised to end the security challenges facing the country.”

The crash occurred three months after a small Nigerian air force passenger plane went down just outside Abuja airport following alleged engine failure, killing all seven people on board.

Nigeria, Africa’s most populous nation, has had poor air safety record in the past, although it has improved in recent years.