An administrative mission of the army, known by its initials FAMa, was hit around 1035 GMT and local time, by an "armed terrorist group" that has not yet been identified, the army said on social media.

It typically uses the term "terrorists" to mean jihadists.

The army convoy returned fire and the announcement mentioned a "provisional toll of four dead on the FAMa side."

Since 2012, separatist and jihadist rebellions in northern Mali have plunged the country into constant conflict that has left thousands of civilians and fighters dead, despite international help.

Separatists signed a peace agreement in 2015, but groups linked to Al-Qaeda and the Islamic State continue to oppose the government, against a background of inter-ethnic rivalry and various types of border smuggling.

The violence has spread to nearby Burkina Faso and Niger in the Sahel region.

On Friday, France said it would resume joint military operations in Mali, after suspending them early last month following the West African country's second coup in less than a year.

But on French President Emmanuel Macron has announced a major drawdown of France's military presence in the Sahel.

France has around 5,100 troops there under its Barkhane operation which spans five countries -- Burkina Faso, Chad, Mali, Mauritania and Niger.

Paris now plans to fold its presence into the so-called Takuba international task force, in which the Czech Republic, Estonia, Italy, Romania and Sweden have also pledged to participate.