Nigeria"s army chief Lieutenant General Ibrahim Attahiru died in a plane crash on Friday on an official visit to the northern state of Kaduna, which has had security challenges in recent months, three military sources told Reuters. The air force said in a statement that its plane crashed near Kaduna airport and that it was investigating the immediate cause of the crash. The crash comes three months after a small Nigerian air force passenger plane crashed just outside Abuja airport following alleged engine failure, killing all seven people on board. read more The sources, who spoke on condition of anonymity, said the army general and his aides died when an air force plane crashed on Friday. President Muhammadu Buhari appointed Attahiru alongside other military chiefs in January after years of mounting criticism over spreading violence by Islamist insurgents and armed gangs.