On The Front Line Of Battle Against Boko Haram

The terror group Boko Haram is "perpetually mutating" according to Cameroon military leaders - and it has a well-organised structure with constantly changing tactics.

Sky News has been given rare access to special forces in Cameroon who are at the forefront of the battle against the extremist militant group.

The group is increasingly conducting its operations over Nigeria's borders and mounting attacks into neighbouring countries like Cameroon.

Our team travelled to the north of the country and its border with Nigeria where the militant group was born.

We joined the Cameroon elite unit, the rapid response battalion or BIR, as it attempted to plug the long, porous border with Nigeria.

The Sky News team was the sole British news organisation to travel with the troops to Amchide, Kolofata and Kerawa - three towns along the border which have all suffered at the hands of Boko Haram.

The army commanders told us the extremist group already had a self-declared caliphate in at least one area of Nigeria - in Gwoza.

"Behind that mountain is Nigeria and a Boko Haram state," said Major Garangsou Clement, commander of Kolofata post.

"There is no Nigerian Government there. It is Boko Haram's caliphate."

The militant group has also developed a new favourite form of attack: roadside bombs or IEDs.

They are much more deadly for the troops and a lot less dangerous for the militants.

We drove past a wrecked army pickup. "IED," one of the soldiers told us.

"Two of our soldiers died there."

In front of Amchide army post there are more charred vehicles: an armoured personnel carrier and a pick-up truck.

The militants almost got to the gate of the post in a large attack last October, before being repelled.

Amchide town appears deserted now.

More troops and heavier weapons have been sent to the border town, but so far the residents do not seem to have been persuaded to return.