Twenty villages were set ablaze and at least four women burned alive, according to a Human Rights Watch report.
The alleged atrocities were part of an escalating conflict that began in late 2016 when an attempt to use English in classrooms and courts was violently repressed by the French-speaking government.
HRW identified several hundred homes across the 20 villages using satellite imagery and then collected testimony from residents who said security forces were responsible.
Its report also documented the burning of schools by armed separatists, in an apparent attempt to enforce their school boycott. Tens of thousands of Cameroonian children have not been able to attend school for the past two years.
The separatists’ numbers have increased as the violent repression continues, particularly since security forces killed dozens of protesters and wounded more than 100 others in October.
With hundreds in jail, and more than 180,000 displaced, many anglophones feel they have no choice but to fight.
In response to the HRW report, Cameroon’s government said the level of force it used remained “proportional to the extent of the threat”.
The report’s author, Jonathan Pedneault, said the government needed to “recognise the fact that its soldiers have committed severe abuses. It needs to order a stop to the abuses and ensure accountability for crimes”.
The Cameroonian military is dealing with multiple accusations of abuses. Four men were recently arrested in connection with a widely shared video showing two women and two children being killed by armed men, who accuse them on camera of being members of the extremist group Boko Haram.
The minister of communication, Issa Tchiroma, has denied the footage showed Cameroonian soldiers, while the minister of defence, Joseph Beti Assomo, has accused the writer and activist Patrice Nganang of creating the video in order to “overwhelm” the armed forces.
Last week, as it travelled through the anglophone south-west region, although he and his six generals were travelling in an armour-plated vehicle with an armed escort, and their attackers had “homemade hunting guns”, so they escaped unharmed.
Paul Biya, who has ruled the country since 1982, has announced he is to run again for office. If he wins, he would be 92 by the end of a seventh presidential term.