In late August, a suicide bomber tried to attack a crowded Catholic church in the Sumatran city of Medan, but his vest failed to detonate.

This past Sunday, an 18-year-old man attacked a priest with an ax during a church service in Medan before being tackled and subdued by worshipers.

But the incident at the church in Medan, Indonesia's third-largest city, marks the second Islamic State-inspired attack in the country this year.