An attack on a military patrol in northern Mali killed two civilians and wounded up to eight French soldiers on Sunday, Mali's defence ministry said.

The attack comes two days after Islamist militants killed at least six people during a raid on a military headquarters in central Mali, a country where French troops are helping combat militants across its vast desert reaches.

"I confirm that it was a car bomb that drove into a joint Barkhane/Malian army patrol," defence ministry spokesman Boubacar Diallo said. Barkhane is the name of the near 4,000-strong French force stationed in its former colonies across the Sahel region.

About a dozen people were wounded in Sunday's attack, including four to eight French Barkhane troops, Diallo said.

France's army spokesman, Patrik Steiger, confirmed that civilians had been killed in an attack in Gao and the army was assessing the state of the 30-strong French patrol that came under attack.

He said the explosion happened near three French vehicles.

Photos posted on social media showed an armoured vehicle on a sandy road surrounded by black smoke.

No one has claimed responsibility for the attack, which occurred a month before presidential elections scheduled for the end of July.

But violence by Islamist militants has proliferated in the sparsely-populated Sahel in recent years, with groups linked to al Qaeda and Islamic State using central and northern Mali as a launchpad for attacks across the region.

Western powers have provided significant funding to a regional force made up of soldiers from Mali, Niger, Burkina Faso, Chad and Mauritania combating Islamist militants. But the so-called G5 force has been hobbled by delays disbursing the money and poor coordination between the five countries.

French President Emmanuel Macron, who last year complained that G5 was taking too long to set up, is due in Mauritania on Monday to discuss security in the region.