A group called the Collective of Communities against Impunity and Stigmatisation (CISC) said relatives on Wednesday made "allegations of summary executions of civilians attributed to the Burkinabe Defence and Security Forces (FDS)."

Neither the army nor Burkina's government have responded to the accusations made public in CISC's statement on Thursday.

The killings occurred when a large convoy of over 100 vehicles travelled through three localities, escorted by dozens of pickup trucks carrying army troops in uniform, CISC said.

Twelve people were killed in the village of Sakoani, seven in Piega and six others in the hamlet of Kankangou, it alleged.

Residents of Sakoani, contacted by AFP, reported the discovery of 11 bodies after the convoy's passage on Wednesday.

"The death toll continues to rise as information reaches us from the field," CISC said. Concurring testimonies, it said, described the victims as "unarmed civilians."

CISC said it was continuing to collect information and called for an independent and impartial judicial inquiry.

Alleged extrajudicial killings have been reported by people in several regions of Burkina, CISC said.

A volunteer force supporting the army has been accused of killing 28 people in the nation's northwest on New Year's Eve.

A landlocked country lying in the heart of West Africa's Sahel, Burkina Faso is one of the world's most volatile and impoverished countries. It has experienced repeated coups since gaining independence from France in 1960.

The armed forces are struggling with a bloody seven-year-old insurgency by jihadists linked to al-Qaeda and the Islamic State group.

Attacks have left thousands of dead, displaced at least two million and fuelled discontent in the military that led to two coups in 2022.