According to the National Police, the bombers arrived at the cathedral on a motorbike. A church security guard was trying to prevent the vehicle from entering the church’s grounds when the bomb exploded.

“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 Brig. Gen. Argo Yuwono said on Sunday.

The blast occurred just after the congregants finished a service for Palm Sunday, which is the first day of Holy Week leading up to Easter and commemorates Jesus’ entry into Jerusalem.

"We were finishing the service and people were going home when it happened," said cathedral pastor Wilhelmus Tulak, as reported by AFP.

The twenty wounded, including church officials and congregants, were sent to three nearby hospitals. The church security guard was among them. He suffered wounds to the stomach and the head.

Authorities have not identified the two bombers or the type of bomb used.

Police said they were still investigating whether an extremist group was behind the attack and whether it was linked to a recent raid on suspected terrorists. In January, National Police counterterrorism squad Densus 88 raided a terrorist hideout in Makassar and killed two men believed to have been involved in a 2019 church bombing in the Philippines.

Read also: Suspected terrorists shot dead in Makassar

No radical groups have claimed responsibility for the Sunday bombing so far.

President Joko “Jokowi” Widodo expressed his sympathy for the wounded and said terrorism had no place in the country.

“Terrorism is a violation against humanity and has no relation to any religion. All religions reject terrorism for any reason,” he said in a public address on Sunday.

He instructed the police to increase security at churches as Easter approached to ensure the safety of Christians during worship.

“I ask society to stay calm in their worship because the state guarantees congregants’ safety to worship without fear,” Jokowi said, adding that the medical expenses for the victims would be covered by the state.

Religious leaders and public figures, including former vice president Jusuf Kalla, a Makassar native who is also the head of the Indonesia Mosque Council (DMI), lamented the incident.

“As the head of the DMI, I want to express my condolences as well as my condemnation [of the attack]. No religion has teachings that encourage such incidents […] This is high-tier criminality that violates humanity. I hope Makassar will return to peacefulness soon,” Kalla said.

Read also: Bomb blast at Makassar church causes casualties

The Indonesian Communion of Churches (PGI) has appealed to Indonesian Christians to stay calm and not allow themselves to be provoked by the attack. Chairman Gomar Gultom said he believed authorities would be able to “investigate this case and create safety and comfort for all Indonesians, especially those living in Makassar”.

Nahdalatul Ulama (NU), the country’s largest Islamic organization, expressed a wish for unity in diversity.

“All humans are brothers and sisters. The solidarity of humanity should not be reduced because of differences in religion, tribe, race or political interests,” NU executive Robikin Emhas said in a statement. “Any violence that threatens social harmony is wrong, especially when it is a terrorist bombing. Such actions should be condemned.”

Makassar, the largest city in Sulawesi, serves as an important port connecting the eastern and western parts of the Indonesian archipelago. Sulawesi is home to a number of Muslims as well as substantial Christian minorities.

Read also: Surabaya church bombings: What we know so far

Churches have been common targets of suicide bombings in Indonesia, the world’s most populous Muslim-majority nation.

In 2018, a family set off suicide bombs at several churches in Surabaya, East Java, during Sunday services, killing dozens. The family belonged to a Quran study group that was linked to local extremist network Jamaah Ansharut Daulah (JAD). The group has pledged allegiance to Islamic State.