A group of light armoured vehicles skated over the moonscape of the Sahara, part of one of the largest detachments the French military has deployed here since colonial times. Its mission is growing ever more urgent: to cut smuggling routes used by jihadists who have turned this inhospitable terrain into a sprawling security challenge for African and international forces alike.
Many of the extremist groups are affiliates of Al Qaeda, which has had roots in North Africa since the 1990s. With the recent introduction of Islamic State franchises, the jihadist push has been marked by increasing, sometimes heated, competition.
But, analysts and military officials say, there is also deepening collaboration among groups using modern communications and a sophisticated system of roving trainers to share military tactics, media strategies and ways of transferring money.
Their threat has grown as Libya - with its ungoverned spaces, oil, ports, and proximity to Europe and the Middle East - becomes a budding hub of operations for both Al Qaeda and the Islamic State to reach deeper into Africa.
And as Africa's jihadists come under the wing of distant and more powerful patrons, officials fear that they are extending their reach and stitching together their ambitions, turning once-local actors into pan-national threats.
The November 20 assault on the Radisson Blu hotel that killed at least 19 people in Bamako, Mali's capital, was just one of the more spectacular recent examples of the ability of these groups to sow deadly mayhem. Across the region, hundreds of people have been killed in terrorist attacks in the past year.
Gen. David M Rodriguez, who heads the United States Africa Command, warned in a congressional statement in March of an "increasingly cohesive network of Al Qaeda affiliates and adherents" that "continues to exploit Africa's undergoverned regions and porous borders to train and conduct attacks."
"Terrorists with allegiances to multiple groups are expanding their collaboration in recruitment, financing, training and operations, both within Africa and transregionally," General Rodriguez warned months before the Mali attack.
The transfer of expertise can be witnessed in the spread of suicide bombings in Libya, Tunisia and Chad and in the growing use of improvised explosive devices in Mali, analysts and officials pointed out.
Such exchanges have been enhanced as groups shift shape, sometimes merge, and come under the wing of more powerful and distant patrons.
In one instance, two of the longest-standing North African groups, Al Qaeda in the Islamic Maghreb and Al Mourabitoun, after a long publicised split, announced that they had reunited and that the Bamako hotel attack was their first joint venture.
The leaders of the two groups - Abdelmalek Droukdel and Mokhtar Belmokhtar, both Algerians - have loyalties that reach far beyond Africa, however.As does Seifallah Ben Hassine, leader of Ansar al-Shariah in Tunisia, the organisation believed to be behind three deadly attacks in Tunisia last year, including a massacre of 38 people at a beach resort in June and an attack on the Bardo Museum in Tunis in March that left 22 dead. All three men are veterans of fighting in Afghanistan in the 1980s, swore allegiance to Osama bin Laden and now profess loyalty to Al Qaeda's current leader, Ayman al-Zawahri.
Droukdel, routed by French forces in Mali in 2013, is reportedly holed up in the mountains in southern Algeria. Belmokhtar and Ben Hassine have made rear bases in Libya, where they have been targeted by American airstrikes. Today, despite French and American efforts to disrupt their networks, they still stretch across the continent.
To keep the pressure on the jihadists and help resist the threat, France has installed 3,500 troops across 10 bases and outposts in five vulnerable countries - Mauritania, Mali, Niger, Burkina Faso and Chad. The recent French patrol, tiny dots in the Sahara's expanse of dunes and blackened rock, included 30-ton supply trucks carrying food and fuel, armoured vehicles mounted with 80-millimeter cannons and a medical truck.
Similarly, American Special Operations Forces are working in Niger, and last year President Obama ordered 300 United States troops to Cameroon to help defend against the Nigerian Islamist movement Boko Haram, which has spread across borders. French troops have led repeated operations to break communication and supply lines from Libya that have fortified such groups.
The November operation was part of coordinated maneuvers in eastern Mali and northern Niger to try to disrupt jihadist links between the two nations. The smuggling route patrolled by the French is one of the main arteries for jihadists, arms and drugs. French troops call it the "autoroute" to southern Libya, which they describe as a "big supermarket" for weapons.
The route crosses one of the most remote places on earth. Devoid of human habitation or water for hundreds of miles, it is a treacherous terrain of unbearable heat in the summer and nearly impossible navigation. Yet small convoys of smugglers attempt the crossing several times a week. For the French, it is like looking for a tiny craft in an ocean, said Lt Col Étienne du Peyroux, the commanding officer leading the Niger operation.
"It is like a naval battle," he said, sketching out the hunt on maps on the hood of his desert jeep. "The zone of operations is 40,000 square kilometers, an area the size of Holland, for 300 men."
"We try to find them, to block, to constrain, to work out how they will be channelled by a particular piece of terrain," he said.
The French rarely catch anyone. But, they say, their operations are at least disrupting the jihadists' movements, evidenced by a drop in traffic and tracks in the sand showing smugglers' vehicles having turned back.
