Amnesty International says a "horrifying" video circulating on social media shows Cameroon's security forces shooting at least a dozen unarmed civilians during an operation in the Far North region.
The rights group said on Friday its analysis shows the video was apparently made by soldiers. Cameroonian authorities deny the shooting.
The video shows soldiers firing automatic weapons at people lying down and cowering against a wall. Amnesty says it was likely recorded before May 2016.
This follows the appearance of another video in July that Amnesty said showed Cameroonian forces shooting two women with small children strapped to their backs as suspected Boko Haram extremists.
Cameroon's government has promised investigations, but its ambassador to Canada this week dismissed the earlier video, telling reporters in Washington: "You know what Photoshop can do."
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