"Boko Haram militants killed at least three civilians and abducted about a dozen others – presumably all Cameroonians," the source said.

At least three people were killed and 15 others kidnapped in a fresh cross-border attack by Nigeria's Boko Haram militant group in northern Cameroon, a security source revealed today.

"The attack took place on Monday afternoon when at least 20 armed men tried to get food supplies, stealing all the [food] stocks found in the Cameroonian village of Greya," the source told Anadolu Agency on condition of anonymity.

"Before leaving, the terrorists also burned down the village's primary school," the source added.

Due to the area's poor communications infrastructure, the Cameroonian army was warned too late of the incident, finally arriving "long after the attackers left," the source lamented.

The militant group has already been blamed for several previous cross-border attacks from Nigeria.

Boko Haram, which means "Western education is forbidden" in Nigeria's local Hausa language, first emerged in the early 2000s preaching against government misrule and corruption.

The group later became violent, however, after the death of its leader in 2009 while in police custody.

In the five years since, the shadowy sect has been blamed for numerous attacks – on places of worship and government institutions – and thousands of deaths.