Updated

A new video from Boko Haram extremists shows gunmen mowing down civilians lying face down in a dorm and a leader saying they are "infidels" or non-believers.

There are so many corpses the gunmen have difficulty stepping to reach bodies still twitching with life.

The video released to journalists late Saturday comes two days after fleeing villagers reported that the extremists are rounding up elderly people and killing them in two schools in Gwoza, in northeast Nigeria.

The setting of the latest video appears to be a school, a long dormitory furnished with bunk beds which the leader says is in Bama, a town 60 kilometers (40 miles) north of Gwoza. Students and schools are frequently targeted by Boko Haram, which means "Western education is sinful" in the Hausa language.