French satirical weekly Charlie Hebdo on Sunday defended itself following outrage over cartoons about a deadly military helicopter crash in Mali, the day before a memorial service for the 13 dead soldiers.

The magazine, which was itself the target of a devastating attack by Islamic extremists in January 2015, published the cartoons on its website.

The French army's chief of staff General Thierry Burkhard expressed his "indignation" at the cartoons in response to last week's deaths.

But Charlie Hebdo's editor Laurent "Riss" Sourisseau defended the magazine's "satirical spirit" on Sunday, while acknowledging the importance of the work of the French army.

The soldiers died last Monday when the two military helicopters in which they were travelling collided and crashed during a night-time operation in Mali against jihadists.

One of the five cartoons on Charlie Hebdo's website showed French President Emmanuel Macron standing in front of a coffin covered with the French tricolour. The text reads: "I joined the ranks to stand out from the crowd" – a slogan the army is using for its current recruitment campaign.

"Profound indignation and incomprehension at the sight of this drawing from @Charlie_Hebdo," the army chief of staff tweeted on Friday.

"My thoughts go first of all to the families of all those soldiers killed in combat to defend our freedoms," Burkhard added.

And in an open letter to "Riss," he accused the magazine of having sullied the period of mourning for the bereaved families.

Riss, in his response on Sunday, wrote: "Our newspaper has to stay loyal to its satirical, sometimes provocative spirit.

"Nevertheless, I would like to say that we are aware of the importance of the work done by French soldiers to fight against terrorism," he added.

The soldiers who died were serving with France's Barkhane mission helping local forces in the Sahel region of Africa fight the increasingly active jihadist forces in the region.

Their bodies have been flown home and on Monday afternoon Macron will pay tribute to them in a special ceremony, which will also be attended by Mali's President Ibrahim Boubacar Keita.

As well as regularly attacking organized religion, Charlie Hebdo has a long tradition of anti-militarist satire. It is regularly denounced by its targets for going too far.

Its depictions of the Prophet Mohammed led to outrage, death threats and ultimately violence.

Two gunmen who claimed allegiance to Al-Qaeda killed 12 people in an attack on its offices in January 2015 in which many of its star cartoonists were killed.

(Cover photo: A man is reading the latest issue of Charlie Hebdo on January 17, 2015 in Berlin, Germany. /VCG Photo )