Nigeria’s Boko Haram Takfiri group has killed scores of civilians in a town near the border with Cameroon, reports say.

On Saturday, the Takfiri militant group continued atrocities in the twin towns of Gamboru and Ngala, in northeastern Nigeria, which they took over earlier this week, AFP reported.

Many of the town’s residents have crossed the border into Cameroon’s Fotokol in an attempt to flee violence in the volatile Borno State’s town.

"They are now killing people like chickens. They started by selective killings and later went on a killing spree,” said a Gamboru resident in Fotokol.

The town's highest Muslim cleric and the head of the traders' union were among those killed, said the witness,

“They threaten to kill anybody who refuses to leave the town. They say we don't belong," said another witness, adding, "Initially they said we were free to stay or leave but now they are saying all residents should leave the town.”

Boko Haram has stepped up its attacks in northeastern Nigeria and has seized territory in Borno.

Boko Haram has claimed responsibility for a number of deadly gun and bomb attacks in various parts of Nigeria since 2009.

Over the past four years, violence in the north of Africa’s most populous country has claimed thousands of lives.