An Indonesian militant and his wife carried out January suicide bombings at a Catholic cathedral in the Philippines that killed 21 people, Jakarta said Thursday, citing DNA tests.

Indonesian police said testing performed on the couple's remains confirmed their involvement, after announcing in July that they believed the attackers were married couple Rullie Rian Zeke and his wife Ulfah Handayani Saleh.

"They shared DNA with their parents so it's them," Indonesian national police spokesman Dedi Prasetyo told reporters Thursday.

The couple had earlier tried to go to Syria to join the Islamic State group (IS) and subsequently underwent an Indonesian government deradicalization program.

They were initially identified as suspects in the Philippines church attack by two militants linked to Indonesian terror network Jamaah Ansharut Daulah (JAD).

• Mass held at Jolo Cathedral nearly 6 months after deadly twin blasts

Members of JAD staged a wave of suicide bombings at churches in Indonesia's second-biggest city Surabaya last year, killing a dozen congregants.

In January, two explosions ripped through a cathedral in Jolo, killing worshippers at Sunday mass and security forces, raising fears about growing links between militants in Southeast Asia.

IS claimed responsibility for the cathedral blast, saying two suicide bombers detonated explosive belts.

The Jolo attack was carried out days after voters approved expanding Muslim self-rule in the south aimed at ending a decades-old rebellion for independence or autonomy for the sizable Islamic minority of the mainly Catholic Philippines.

The church attack happened as the southern Philippines was put under martial rule after pro-IS militants seized the southern city of Marawi in May 2017.

Several months after the Philippines attack, Easter suicide bombings by Islamist extremists killed 258 people in Sri Lanka.