SAHARA DESERT, Niger — A group of light armored 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.