ARI SHAPIRO, HOST:
The president of the Philippines, Rodrigo Duterte, got a firsthand look today at the devastation from a cathedral bombing in the southern city of Jolo. The explosion, during Sunday Mass, killed at least 20 people and wounded more than a hundred others. A militant group aligned with ISIS has claimed responsibility. Michael Sullivan has more on the group's troubled history in the region.
MICHAEL SULLIVAN, BYLINE: In May 2017, fighters from the Abu Sayyaf and other ISIS-linked groups occupied much of the city of Marawi on the island of Mindanao. It took the Philippines' military five months to dislodge them and declare victory, leaving much of the city in ruins and many of the fighters dead - down but not out.
SIDNEY JONES: I think you can be very sure that what happened in Jolo is not the last gasp of a group on the edge of extinction.
SULLIVAN: Sidney Jones is director of the Institute for Policy Analysis of Conflict in Jakarta, Indonesia.
JONES: I think you have to put this in the context of a lot of other pro-ISIS activity in Mindanao since the end of the Marawi siege.
SULLIVAN: After that siege, she says, the authorities said that ISIS in the southern Philippines was defeated. But it wasn't. The coalition of groups involved dispersed into different areas, Jones says, but they didn't go away.
JONES: And there have been a persistent series of bombings in different parts of the Philippines of which this is the biggest.
SULLIVAN: Including the first suicide bombing carried out by a foreigner last July that killed 10 people. Zachary Abuza, a professor at the National War College who tracks Southeast Asian terror groups, predicts Sunday's bombing will become a useful propaganda tool for ISIS to recruit more.
ZACHARY ABUZA: If you are a foreign fighter from Southeast Asia, you are now going to be more attracted to go into the Abu Sayyaf simply because they are demonstrating their ability to continue the fight.
SULLIVAN: He says the timing of Sunday's attack - less than a week after an overwhelming majority of Muslims in the south voted for an autonomy plan aimed at ending decades of conflict - is no accident.
ABUZA: They're trying to provoke a heavy-handed government response that will, in turn, alienate the local community.
SULLIVAN: And that kind of response, says Sidney Jones of the Institute for Policy Analysis of Conflict, would be a huge mistake - one that's been made before.
JONES: One of the worst tactics used by the Philippines government is the idea that you eradicate terrorism by killing those involved, not by understanding who's involved and not by trying to look at the network.
SULLIVAN: Networks that show no sign of being shut down anytime soon. For NPR News, I'm Michael Sullivan in Bangkok.