A Boko Haram expert has highlighted one difficulty in curbing the activities of the Nigerian militant group.

That difficulty is the lack of coordination between the factions under the extremist group's banner.

"Boko Haram is not one unified coordinated organisation," Peter Lewis, head of African studies at the Johns Hopkins School of Advanced International Studies, said according to the Washington Post.

"They are a series of factions with different leaders and different armed groups," Lewis added.

The Johns Hopkins expert described Boko Haram as a group that is very much capable of adapting to changing circumstances. This, he said, will make it difficult for opponents to identify an "endgame", even the multi-national task force assembled by Nigeria's neighbours specifically to combat its threat.

The multi-national task force is a regional military force assembled by Nigeria, Chad, Niger, Cameroon and Benin in February after the militant group expanded its attacks to towns across Nigeria's borders. 

According to the Washington Post, the actual size of Boko Haram has not been firmly estabilshed. There are estimates that the group numbers only 5,000, but other experts believe the organisation's membership is actually at 25,000. By contrast, the multi-national task force numbers 8,000 soldiers, a large part of which comes from Nigeria and Chad.

Still, the Washington Post reported the Nigerian group may be losing the war as a result of the combined efforts of Nigeria and its neighbours.

Experts are pointing to Boko Haram leader Abubakar Shekau's pledge of allegiance to the Islamic State as a sign of the militant group's weakness. 

"Shekau's pledge is at least in part a cry for help, as Boko Haram is losing control of many of the residential areas it had captured since it began holding on to territory in July 2014," Martin Roberts, of IHS Country Risk, told The Washington Post.