More than four decades of continuous conflict has made Mindanao a region of war widows.
A counterterrorism unit raiding a hideout of armed fighters in central Indonesia on Wednesday shot dead two men suspected of involvement in twin bombings at a Philippine church in 2019 that killed more than 20 people.
Police said in a statement the raid in Makassar in South Sulawesi by the Densus 88 unit led to a fatal shoot-out with two suspected fighters who resisted arrest.
Makassar police chief Witnu Urip Laksana told Reuters news agency the suspects were involved in the bombings of a church on southern Jolo Island in a restive, predominantly Muslim region of the Catholic-majority Philippines.
Police carried out “firm and calculated” action against the two suspects, Witnu said, adding an investigation was continuing.
Police suspect the men were members of the ISIL-inspired Jamaah Ansharut Daulah (JAD), which has carried out a series of attacks in Indonesia.
Philippine authorities have concluded the January 2019 church attack was a suicide bombing by an Indonesian couple, with the help of a faction of the Abu Sayyaf Group, which has pledged allegiance to ISIL (ISIS).
Abu Sayyaf fighters also trained with the Southeast Asian armed group Jemaah Islamiyah (JI), which was founded by an Indonesian preacher, and both groups had been previously linked to al-Qaeda.
More than 100 people were wounded in the Jolo church bombing, which was among the first and so far deadliest suicide bombings in the Philippines, where such attacks were almost unheard of until 2018.
Philippine Defence Secretary Delfin Lorenzana did not immediately respond to a request for comment on Wednesday.
The region of Mindanao in the southern Philippines has for decades been beset by Muslim separatists. With its porous borders and close proximity to Indonesia and Malaysia, the Filipino fighters have been able to establish close links with regional allies.
Authorities are concerned about armed groups taking hold in impoverished, mainly Muslim areas, where operatives from nearby countries and beyond have linked up with local groups to plan attacks and recruit and train fighters.
In October 2020, Philippine authorities also arrested an Indonesian woman who was believed to be linked to a separate suicide attack on a military convoy in Jolo that killed 15 people and wounded dozens of others.
The Indonesian woman was the widow of another Indonesian who was killed by Filipino soldiers in Sulu in August 2020.
She is also believed to be the daughter of two suicide bombers involved in the church bombing.