Indonesian police have discovered explosives in a raid related to the attack outside the Sacred Heart of Jesus Cathedral on Sunday.
The raids follow two suicide bombings in the city of Makassar, the capital of South Sulawesi province, during a service for Palm Sunday.
According to the country's chief security minister, Mohammad Mahfud, about twenty people were wounded in the Sunday attack.
"There were two people riding on a motorbike when the explosion happened at the main gate of the church - the perpetrators were trying to enter the compound," National Police spokesman Argo Yuwono said.
No group has claimed responsibility so far.