"Burkinabe authorities should immediately open a transparent and impartial investigation of this brutal incident and appropriately punish all those responsible," an HRW statement said.

The rights group said an 81-second video, widely circulated on social media, shows at least 18 men wearing identifiable army uniforms watching while two use knives on the body.

The soldiers can be seen "mutilating and disemboweling a dead body", the group said, demanding that "all those found responsible for wrongdoing should be appropriately prosecuted, regardless of their rank".

The country's military leadership said earlier this week that it "strongly condemns these macabre acts, which are contrary to military and moral values and to the rules of engagement for combatants in the fight against terrorism."

The army said the origin of the videos was being looked into as the footage does not specify the location, date, or identities of the individuals involved. HRW pointed out, however, that no criminal investigation was announced by the junta that took power in a coup in 2022.

According to the rights group, citing its own sources, the footage was shot between April and May near Nouna in the northwest.

A jihadist insurgency that erupted in Mali in 2012 spread to Niger and Burkina Faso in 2015.

The Burkinabe army has always denied repeated allegations of extrajudicial executions, sometimes attributing the acts to armed groups using military equipment.

"The gruesome video showing soldiers mutilating a body underscores the pervasive lack of accountability for atrocities that military units have committed in Burkina Faso in recent years," said Ilaria Allegrozzi, a senior HRW specialist.

In April, HRW accused the Burkina Faso military of killing at least 223 civilians, including 56 children, in the north of the country.