YAOUNDÉ: Cameroon's army said on Monday it had arrested several soldiers and police for torturing a suspected "terrorist" in the country's conflict-scarred anglophone region.

A 10-minute video posted on social media showed men in military uniforms armed with Kalashnikov rifles and a machete slapping a semi-naked man and kicking him in the head.

"Two gendarmes, two soldiers and four police officers" were "caught up in this unacceptable act", army spokesman Cyrille Serge Atonfack Guemo said in a statement, adding that they had been "immediately arrested".

The torture video, which also showed the victim being struck with the flat edge of the machete on the soles of his feet, was filmed in Cameroon's English-speaking northwest, according to the army statement.

Human Rights Watch researcher Ilaria Allegrozzi said the group "welcomed" the judicial inquiry.

Separatist armed groups have battled with security forces in the English-speaking regions for three years, with both sides accused of violence against civilians.

In a separate statement, English-speaking minister Paul Tasong said three traditional chieftains from the Lebialem region had been "shot to death" and their bodies thrown in a river.

The killers were led by a separatist leader known as "Field Marshal", Tasong added, saying the victims had been "accused of making sure the schools were working properly" in their village.

The anglophone rebels regularly attack schools as they associate them with the central government.

Rights groups say more than 3,000 people have died and 700,000 have fled their homes since 2017 as a result of the violence.