File photo: Burkina Faso soldiers are seen deployed on September 30, 2022 in Ouagadougou, Burkina Faso. AFP
Fifteen bodies bearing bullet impacts were found on Monday near Linguekoro, a village in the western province of Comoe, regional governor Colonel Jean-Charles Some said in a statement.
They were among 24 people who were aboard two minibuses travelling from Banfora that were stopped in Linguekoro by armed men on Sunday evening, he said.
"The passengers, comprising eight men and 16 women, were told to get off," he said.
"Eight women and one man were released and told to walk to Mangodara," 30 kilometres (18 miles) away, he said.
The two minibuses were then torched and the 15 other passengers taken away.
Separately, 10 police officers, two members of an auxiliary force supporting the army, and a civilian died in northern Burkina Faso from a "terrorist attack on Monday" in the locality of Falagountou, which also goes by the spelling of Falangoutou, army headquarters said.
At least five police were wounded and about 10 are missing, while the bodies of about 15 "terrorists" were found during a sweep, it said.
The attacks mark a further escalation in an insurgency that has beset Burkina, one of the world's poorest and most troubled countries, for more than seven years.
Violence linked to Al-Qaeda and the Islamic State group has killed thousands of people and forced around two million more to flee their homes.
More than a third of the country lies beyond the control of the government.
Since the start of the year, at least 77 people have died, according to a toll compiled by AFP from official statements and security sources.
Also in January, 62 women and four babies were abducted as they foraged for food in Arbinda, in the north of the country.
They were rescued by the army several days later at a location 200 kilometres (125 miles) away, according to the state-run media.
Frustration within the army at the mounting toll of security forces triggered two coups last year.
The ruling junta has fallen out with France, the country's traditional ally and military supporter, which last week said it would withdraw its troops at the authorities' request.
Around 400 French special forces are based near the capital Ouagadougou in a deployment dubbed Operation Sabre, part of a broader military presence to fight jihadists across the Sahel region.
Thousands of demonstrators rallied in the capital on Saturday to celebrate the pullout, and some called for Burkina Faso to follow Mali in weaving a close alliance with Moscow.
Relations between France and Mali, the epicentre of the jihadist campaign that erupted in the Sahel in 2012, nosedived after the military forced out the country's elected president, Ibrahim Boubacar Keita, in 2020.
The junta brought in Russian paramilitaries, whom Paris and others describe as mercenaries of Russia's privately-run Wagner operation.
The Wagner group has been associated with abuses or atrocities in Mali and the Central African Republic, where France last year also withdrew its forces in the face of hostility.