…The ambushes were part of rapidly growing violence by groups linked to al Qaeda and Islamic State in the Sahel, a band of arid terrain south of the Sahara Desert. In the past four years, thousands of people have been killed in attacks in three Sahel countries – Niger, Mali and Burkina Faso, conflict data show. France, the United States and neighboring countries have deployed thousands of troops to try to secure the area. Millions have been displaced and thousands of schools have shut, as these groups strive to win control of rural communities and rid the region of international forces.

Amid the chaos, a pattern has emerged. Since early 2018, Islamist groups have assassinated or abducted at least 300 community leaders, state officials and family members in the borderlands between the three countries, an area bigger than Germany, according to a Reuters analysis of thousands of violent incidents and interviews with more than two dozen witnesses and officials. In the six years before, they killed or abducted fewer than 20 leaders.

The Reuters analysis used records from the Armed Conflict Location & Event Data Project (ACLED), a research and consulting group that collects reports from media and non-governmental organizations to track political violence. Those targeted include chiefs, mayors, council members and religious leaders. The tally is likely an undercount: It omits dozens of attacks carried out by unidentified groups in areas where Islamists operate.

The attacks have weakened ties between rural communities and central governments in the Sahel and helped militants gain control of large areas. It follows the same playbook Islamic State and al Qaeda militants have employed to wield power in other parts of Africa and the Middle East, researchers say.

Without strong leaders to push back, populations in the Sahel are vulnerable to recruitment, extortion and attack, and security forces are stripped of a key source of intelligence and support, say government officials and analysts.