The United States' top general for Africa has warned of "violent extremism" and the threat of Russian mercenaries in the Sahel region, speaking as war games wrapped up in Morocco.

"We are seeing the rise of violent extremism in Western Africa, predominantly in the Sahel region," said General Stephen J. Townsend, commander of the US Africa Command (AFRICOM).

US Army General Stephen J. Townsend (centre) commander of the US Africa Command (AFRICOM)
US Army General Stephen J. Townsend (centre) commander of the US Africa Command (AFRICOM) AFP / FADEL SENNA

The Sahel region is a vast territory stretching across the south of Africa's Sahara Desert, incorporating countries such as Burkina Faso, Chad, Mali, Mauritania and Niger.

"We are seeing the arrival of malign actors, and specifically I am thinking of Russian mercenaries from Wagner," Townsend told AFP in the North African nation on Thursday, at the conclusion of a four-week long "African Lion" international military exercise.

A Royal Moroccan Air Force CH-47 Chinook military helicopter takes off: more than 7,500 personnel from a dozen countries took part in the "African Lion" exercises
A Royal Moroccan Air Force CH-47 Chinook military helicopter takes off: more than 7,500 personnel from a dozen countries took part in the "African Lion" exercises AFP / FADEL SENNA

"This training is not specifically oriented on those problems, but it will help all of our armed forces if we are called to combat this kind of problem in the future," Townsend said.

Islamic State-linked jihadists, whose power was once thought to be waning in the Sahel, have recently expanded their reach and marking their presence with an unprecedented series of civilian massacres.

Mali has been especially hard hit, a former French colony where the strategic landscape has changed dramatically following two coups in August 2020 and May 2021.

A US army AH-64 Apache attack helicopter flies over members of the Moroccan Royal Armed Forces during the second annual "African Lion" military exercise  on June 30
A US army AH-64 Apache attack helicopter flies over members of the Moroccan Royal Armed Forces during the second annual "African Lion" military exercise on June 30 AFP / FADEL SENNA

Bamako developed closer ties with Moscow, bringing in military personnel that France says are mercenaries from Russia's Wagner group.

Troops simulated a joint land and air attack against enemy columns in a live fire exercise
Troops simulated a joint land and air attack against enemy columns in a live fire exercise AFP / FADEL SENNA

AFRICOM, which is based in the German city of Stuttgart, is responsible for US military operations across Africa.

Map of Western Sahara
Map of Western Sahara AFP / Adrian LEUNG

More than 7,500 personnel from a dozen countries took part in the "African Lion" exercises, running from June 6 to 30, with operations in Morocco, Ghana, Senegal and Tunisia.

As well as US troops and officers from the host nations, soldiers from Brazil, Britain, Chad, France, Italy and the Netherlands took part.

The Moroccan leg of the games were attended by military observers from NATO, the African Union and nearly 30 "partner countries", including for the first time Israel.

A US M142 High Mobility Artillery Rocket System (Himars), which the United States plans to supply to Ukraine in its war with Russia
A US M142 High Mobility Artillery Rocket System (Himars), which the United States plans to supply to Ukraine in its war with Russia AFP / Fayez Nureldine

Exercises included land, airborne and maritime manoeuvres, preparation for nuclear biological and chemical decontamination, as well as providing medical and humanitarian aid.

On Thursday, at Cap Draa in the dusty deserts of southern Morocco some 700 kilometres (435 miles) south of Rabat, troops simulated a joint land and air attack against enemy columns in a live fire exercise.

Overhead, F-16 warplanes and Apache attack helicopters roared across the skies.

Through the sand, M1 Abrams tanks and AMX-10 RC wheeled armoured reconnaissance vehicles ploughed across the dunes, accompanied by HIMARS multiple rocket launchers firing salvoes.

Plumes of smoke rose up high after live fire artillery barrages, with the dust whipped up by fierce winds from the Atlantic Ocean.

But Townsend was keen to stress the operations were "hypothetical" war games, an "exercise scenario that is completely made up", and not targeting any nation.

The exercise comes amid heightened tensions between Rabat and Algiers over the disputed Western Sahara.

Former US president Donald Trump recognised Moroccan sovereignty over the territory in 2020 in return for Rabat re-establishing ties with Israel, and Algeria responded months later by breaking ties with Morocco.

Exercises took place close to the border with Western Sahara and Sahrawi refugee camps where the Algerian-backed Polisario Front independence movement is based.

Townsend said the exercise was "not focused on Algeria at all", but was about "increasing our skill as armies" to work together.

"What we are seeing played out in NATO and Ukraine today shows the value of strong allies and partners working together to defend our common interest," he added.

The conflict in Ukraine dominated the NATO summit in Madrid this week, where US President Joe Biden announced a boost of US military in Europe, including on its "southern flank" in Spain and Italy, across the Mediterranean Sea from North Africa.