Having slipped undetected into Mali's capital weeks ago, the jihadis struck just before dawn prayers. They killed dozens of students at an elite police training academy, stormed Bamako's airport and set the presidential jet on fire. The Sept. 17 attack was the most brazen since 2016 in a capital city in the Sahel, a vast arid region stretching across sub-Saharan Africa south of the Sahara Desert.

It showed that jihadist groups with links to al-Qaida or the Islamic State group, whose largely rural insurgency has killed thousands of civilians and displaced millions in Burkina Faso, Mali and Niger, can also strike at the heart of power. Overshadowed by wars in Ukraine, the Middle East and Sudan, conflict in the Sahel rarely garners global headlines, yet it is contributing to a sharp rise in migration from the region toward Europe at a time when anti-immigrant far-right parties are on the rise and some EU states are tightening their borders.

According to the U.N.'s International Organization for Migration (IOM), the route to Europe with the steepest rise in numbers this year is via West African coastal nations to Spain's Canary Islands.