Boko Haram Gunmen Massacre Men In School Hall

Boko Haram militants have released a video apparently showing civilians being shot as they lie face down in a hall as the group's leader boasted the floor was "crimsoned" with blood.

Gunmen are seen struggling to move around the room, which appears to be in a school, because of the sheer number of corpses around them.

"We have made sure the floor of this hall is turned red with blood, and this is how it is going to be in all future attacks and arrests of infidels," the group's leader said in a message.

"From now, killing, slaughtering, destructions and bombing will be our religious duty anywhere we invade."

Most of the victims appear to be adult men, which the Nigerian group said had been killed because they were "infidels".

The harrowing video comes days after terrified villagers fled from Gwoza in northeast Nigeria, amid reports that extremists were rounding up elderly people and killing them in schools.

The militants said the video was filmed in Bama, about 40 miles north of Gwoza.

Thousands of people have been killed by the Sunni jihadi group since the insurgency began five years ago, with an estimated 1.6 million others displaced.