Incident of firing between extremists took place at Karbi Hills of Bokajan on Sunday.
As per sources, Chief of United People's Revolution Front Mangin Khalhao had been killed in the firing.
The deceased chief of UPRF Army is called as Birappan.
Birappan had lost his life amid the firing of his own army of extremists, said sources.
The incident took place in a very remote place of Bokajan of Assam, known as Khengpibong.
