At least one person was killed and nine others were injured Sunday in an explosion at a Christian church on the Indonesian island of Sulawesi, where authorities are investigating whether it was a terrorist attack.

Police said in a statement that the explosion occurred when an unidentified person allegedly blew himself up with a motorcycle bomb, although they have not yet declared the blast a bombing. Two attackers are believed to be involved in the detonation.

South Sulawesi province police chief Merdisyam told local television that the injured included nine passers-by who were in the vicinity and five worshippers attending a mass today on Palm Sunday, which marks the start of Holy Week, at the church, located in the city of Makassar.

-TN