PARIS — A collision of two helicopters killed 13 French soldiers during a night operation in Mali, French authorities announced Tuesday morning.

The mission was part of a broader military effort against Islamist radicals in the Sahel region, according to a statement from the Élysée Palace, the official seat of the French presidency.

The two helicopters, a Tiger and a Cougar, were providing assistance to ground forces engaged in the counterterrorism operation, France’s Defense Ministry said in a statement.

President Emmanuel Macron expressed his “greatest respect” for the fallen soldiers and his “total support” for the French military.

“These 13 heroes had only one aim: to protect us,” Macron said in a separate statement, posted on Twitter. “I bow my head before the sadness of their loved ones and their comrades.”

Ibrahim Boubacar Keïta, Mali’s president, expressed his condolences. He said in a statement that the troops died not only for France, but also “for Mali, for the Sahel, for liberty, and for man.”

Operation Barkhane, France’s ongoing counterinsurgency operation in the Sahel, officially began in 2014 and has claimed 41 French soldiers’ lives.

But France, Mali’s former colonial power, has had a heavy military presence in the region since 2012, when extremists linked to al-Qaeda seized the ancient city of Timbuktu and threatened to move on the capital, Bamako.

About 4,500 French troops are stationed across West Africa, working with regional security partners to quash the Islamist violence that has spread rapidly in Mali and neighboring countries, including Burkina Faso and Niger, in recent years.

U.S. officials say Mali and the broader Sahel region, which lies south of the Sahara Desert, threaten to become a refuge for terrorists to plan and launch attacks across the world. Mali, which is about twice the size of Texas, is considered the epicenter of West Africa’s struggle against terrorism.

U.S. Secretary of State Mike Pompeo said this month that the threat posed by the Islamic State had shifted from the Middle East to West Africa after the militant group’s leader, Abu Bakr al-Baghdadi, killed himself in Syria during an operation by U.S. forces in October. The Islamic State is “outpacing the ability of regional governments and international partners to address that threat,” Pompeo said.

Heavily armed mercenaries once loyal to Libyan leader Moammar Gaddafi returned to their native Mali after his 2011 overthrow and death and forged a shaky relationship with extremists seeking to gain territory in West Africa.

The Monday incident involving French forces occurred less than a week after the local affiliate of the Islamic State took responsibility for an attack that killed 30 Malian soldiers earlier this month in the Gao region, bordering Burkina Faso and Niger. 

The group also asserted responsibility for an ambush in early November that killed at least 53 soldiers, and an al-Qaeda branch said it was behind the September raids that killed 38 soldiers.

More than 100 soldiers have died in Mali since September in routine tangles as the country fights the unrest that erupted in 2011. More than 800 civilians have died in Mali since January, up from about 574 in the previous year, according to the Armed Conflict Location and Event Data Project.

At least 140,000 Malians, meanwhile, have been forced out of their homes in 2019, according to a fall report from the Internal Displacement Monitoring Center — an almost sevenfold increase from the previous year.

Mali has responded to the escalating violence by sending a third of its armed forces into the nation’s restive center and north, where they are backed by French and U.N. forces. The United States provides some logistical help and intelligence.

Paquette reported from Dakar, Senegal.