The chief of army staff, Tukur Burtai says Boko Haram leaders and recruiters live in communities, evading detection by mixing with the local population.
Buratai here revealed that Boko Haram's mode of operation, its use of propaganda and hardcore ideology are the major reasons the insurgency has lasted for many years.
In an interview with Daily Trust, he said the war against Boko Haram has improved from what it used to be years ago, but admitted that there has been a "minimal resurgence".
"Insurgency is not what you defeat and it would just fizzle out; they would revert to other tactics. That is terrorism," he said.
"They will promote propaganda, to the effect that all the institutions of government would be seen to be ineffective. This is what they are doing. They are exploiting the fault lines in our economic and political endeavours to expand the gulf of so-called discord and acrimony amongst various ethnic and religious groups.
"Why are they doing this propaganda, blocking the road and capturing individuals because they are of a particular religion? Unfortunately, they murder those individuals and send it to the world. These are propaganda strategies of the terrorists.
"These individuals may be living with you and you would not know they are terrorists. They have a series of informants and logistics suppliers. They have a series of leadership strata that live in the communities and towns nearby. They pass information and organise those that are hidden along the borders in remote areas or communities who come, attack and go back. They also have a series of recruiters."
The army chief said though the group took up arms in 2009, some of its members were indoctrinated about 10 or 40 years ago, and that what Nigeria currently faces is an "is an existential threat"
"Looking at it from this perspective, you would see that it is a complex operation you cannot wish to just go," he said.
"At the national assembly, I said indoctrination of the citizens did not start in 2009, it started much earlier. And it grew until it reached that point where they took arms against the state.
"It is an indoctrination that has taken roots between 10 and 40 years back. And for you to de-radicalise an individual to bring him back to sanity, you think it would just take you three years, four or 10 years?
"These are people that were brain-washed to believe that when they die they would go straight to heaven. And you think they would believe in you to bring them back to mix with people they refer to as unbelievers? You have to look at this context."
Buratai said while the military continues to target the leaders of Boko Haram, it needs "extensive and intensive surveillance arrangement (and) very good intelligence".
He said: "If you are targeting the head to decapitate, you must have been on their tracks; how close have we ever gotten close to eliminating Shekau? This is a military operation.
"Late last year, there was a report in which the Air Force bombarded their camps and many of their leaders were eliminated. Even the attack on Damaturu, about two of their commanders were eliminated. In Goneri also, one of their commanders was eliminated.
"We will continue to target them individually and as a group until we narrow the overall leader. It requires some intelligence. As I said, this insurgency did not start yesterday; it started over 40 years back."
Vanguard Nigeria News