The two suspected bombers both died, according to Indonesian police, and so far no other deaths have been reported. A security guard who tried to stop two suspected bombers from entering the churchyard is among the injured, Indonesian Police Inspector General Argo Yuwono told media.
The suspects used a motorbike and detonated outside the church which was holding Easter Holy Week services when they were stopped from entering the yard.
There has been no immediate claim of responsibility for the attack. Police say the investigation with the anti-terror unit is ongoing.
Authorities were looking into which networks the bombers came from and if the attack was linked to recent arrests of suspected militants, Reuters news agency reported Yuwono as saying.
Indonesian president Joko Widodo strongly condemned the attack in a video broadcast, describing the attack as as an “act of terrorism,” Reuters reported.
He urged people to remain calm and said the government would ensure that everybody can worship freely, “without fear.”