Local sources said French soldiers had shot and wounded four protesters in Kaya on Saturday -- a claim the army has rejected.

The army logistics convoy, which has been transiting through the city since Thursday on its way to Niger, left without difficulty on Saturday night, French army spokesman Colonel Pascal Ianni said.

The decision to move the convoy dozens of kilometres to the south was made to "lower the tensions and avoid another day of face-to-face confrontation between protesters, Burkinabe gendarmes and French soldiers," he told AFP.

"The situation was quite volatile yesterday," he said.

"Fake news circulated saying the army fired into the crowd and injured four people."

He said there were only a few warning shots fired into the air and that local police were the only ones that had been in direct contact with the protesters.

"We are in the Sahel to fight against armed terrorist groups and ensure the safety of the population -- not the opposite," he said.

On Saturday, a source in Kaya said that "as the protesters tried to get closer" to the French soldiers, they "fired warning shots", and some received gunshot wounds.

A medical source said "the emergency department at the Kaya hospital received four people with gunshot wounds".

France has been fighting jihadist groups in the region since 2013, but plans to reduce the number of troops there to 2,500-3,000 by 2023, compared to more than 5,000 previously.

The former colonial power has faced sometimes virulent protests against its presence, particularly in Mali and Burkina Faso.

Asked about the protests on LCI television, French Foreign Minister Jean-Yves Le Drian said that five Sahel countries, Mali, Burkina Faso, Niger, Chad and Mauritania, had asked for France's "help against terrorism".

"There are manipulators -- by social networks, by fake news, by the instrumentalisation of parts of the media -- who play up against France, sometimes even inspired by European networks, I am thinking of Russia," he said.