"Seven soldiers arrested on suspicion of extrajudicial executions in the Far North region will be brought before a military court in Yaounde... where they will be tried in line with the law," communications official Cyrille Serge Atonfack Guemo told AFP.

The charges are for joint participation in murder, breach of regulations and conspiracy to commit these crimes, he said.

The date of the trial has yet to be set.

"Cameroon does not compromise over behaviour that is incompatible with law relating to war, human law and the protection of people and their belongings," he said

The killings occurred last July in a region plagued by cross-border raids by Boko Haram fighters from neighbouring Nigeria.

The assailants in the video accuse the four of being members of the jihadist group.

The Cameroonian government initially branded the video "fake news" and a "horrible montage" but said it would investigate. It made seven arrests the following month.

Amnesty International for its part said it had "credible evidence" that the men in the video were Cameroonian soldiers.

The United States and Britain were among those which called for a probe and to hold those responsible to account.

Cameroon's armed forces have also been accused of abuses in two western regions where anglophone separatists have launched an armed campaign against the predominantly French-speaking state.

Acts of violence there have been committed by both sides, say monitors.

According to the International Crisis Group think tank, 1,850 people have been killed, while more than 530,000 people have been forced from their homes, according to UN figures.