"France is deeply concerned by information of mass abuses in the village of Moura by elements of the Malian armed forces accompanied by Russian mercenaries from the Wagner group, which are said to have caused the death of hundreds of civilians," the French foreign ministry said in a statement.

Mali's army said Friday that it had killed 203 combatants in an operation in Moura late last month, which it termed a "terrorist fiefdom."

Its announcement came as numerous social media reports in Mali this week alleged that dozens of people, including civilians, had been killed in Moura.

AFP was unable to verify the army's claimed death toll or the social media reports about civilian deaths.

The French statement called for the rapid opening of "national and international investigations" to bring the perpetrators of the killings to justice.

"The fight against terrorist groups operating in the Sahel can in no way justify violations of human rights," the ministry said.

"Indiscriminate violence against civilian populations only strengthens these groups," it added.

The EU also said Monday that it was "very worried" about reports of a massacre in Moura, urging the West African state to allow investigators to access the region.

EU foreign policy chief Josep Borrell called the reports of abuses "very worrying."

"The fight against terrorism can in no way justify massive human rights violations," he said in a statement.

Borrell's statement comes after the US State Department on Sunday also called for an inquiry, saying the reports of a massacre were "extremely disturbing."

Mali, a landlocked nation of 21 million people, has struggled to contain a brutal jihadist insurgency that emerged in 2012, before spreading to neighbouring Burkina Faso and Niger.

France announced in February that it was withdrawing its troops from Mali after a breakdown in relations with the country's ruling junta, ending a near 10-year deployment.

France sent soldiers to its former colony in 2013 to beat back advancing Islamic extremists, but its initial battlefield success was followed by a grinding anti-insurgency operation and rising hostility from Malians.

Anger in Paris about the alleged arrival of Russian mercenaries from the Wagner group, which analysts say has close ties to the Kremlin, also hastened the French departure.