French fighter pilots prepare for a mission against Islamist militants in the Sahel. File picture: Reuters

Paris - A top leader of a regional affiliate of the Islamic State terrorist group and three others have been killed during a French military operation in the West-African country of Mali, authorities said Monday.

The death of Mohamed Ag Almouner, a leader of the Islamic State in the Sahara region, and another member of the group was verified by military personnel, the French military said in Paris.

Two civilians - a woman and a teenager - were also killed in the operation, which took place in the Menaka region in the country's north-east on Sunday. Three others, including one civilian, were injured.

Around 4 000 French soldiers are currently based in the Sahel with the aim of combatting Islamist terrorist groups in the region. Approximately 1 000 German troops are based in Mali.

Mali has been unstable for years, ever since an extremist uprising in the north in 2012 put much of the country into the hands of Islamist and other rebel groups.