The armoured vehicles and logistics trucks had crossed the border on Friday after being blocked in Burkina Faso for a week by demonstrations there against French forces' failure to stop mounting violence by Islamist militants.

Anger about France's military presence in its former colonies has been rising in Niger, Burkina Faso and other countries in west Africa's Sahel region where France has thousands of troops to fight militants.

Last weekend hundreds of people in the Burkinabe city of Kaya blocked the French convoy, which is on its way from Ivory Coast to Mali.

It was able to leave Burkina Faso on Friday but ran into new protests on Saturday morning less than 30km across the border in the western Niger town of Tera, where it had stopped to spend the night.

Hamma Mamoudou, the mayor of Tera, told Reuters that two of the protesters were killed and 16 others injured during the stand-off, "most likely" by gunshots.

French military spokesman Colonel Pascal Ianni told Reuters earlier that French soldiers and Nigerien military police had fired warning shots to disperse protesters who were trying to pillage and seize trucks.

Ianni said the convoy was then able to continue on its way toward the capital Niamey.

He did not immediately respond later to a question about the deaths.

Video shared by a local official showed the protesters, mostly young men, shouting "Down with France!" as black smoke rose from a burning barricade.

France intervened in Mali in 2013 to beat back militants who had seized the desert north, before deploying soldiers across the Sahel.

While it has killed many top jihadist leaders, violence has continued to intensify and spread in the region.

In the demonstrations in Burkina Faso and elsewhere, protesters have cited claims that France is secretly supporting the militants to justify its continued military presence in its former colonies.

Australian Associated Press