Assaya Ngweba says Islamic extremists transformed his once-peaceful village in Burkina Faso, near the border with Mali, into “a place of misfortune and death.”

Now the 78-year-old is among half a million people who have fled the area this year as the extremists linked to al Qaeda and the Islamic State increase attacks and expand their range in West Africa. Concerted military actions by five regional countries, along with a French operation, have failed to stem the violence.

The border between Burkina Faso and Mali is the latest flash point in the vast, arid Sahel region that stretches across Africa south of the Sahara Desert. In the past week, at least 19 civilians have been killed by suspected extremists in Burkina Faso’s north.

Read more: San Francisco Chronicle