Cameroon's army is deploying drones to identify and target Boko Haram positions along the country's border with Nigeria, a region that is frequently targeted by the Islamist militant group.

Boko Haram violence has left at least 17,000 dead and forced more than 2.6 million from their homes since the group launched its insurgency in Nigeria in 2009.

Nearly 1,200 people have been killed since the Nigerian fighters took their offensive into Cameroon in 2013, according to government figures.

In recent years, Boko Haram fighters slipped back and forth across the frontier, often using Cameroon's remote north as a rear base, acquiring arms, vehicles and supplies there.

Since late November the Cameroon army has carried out operations in several border areas aimed at weakening the Nigeria-based militants.