Joko Widodo, Indonesian President, has described the bombing of a cathedral in Makassar, Sulawesi Island as terrorism.
More than a dozen Christians were inside celebrating the start of Holy Week when the blast went off around 10:30am. At least 14 church officials and congregants were injured by debris, police said.
Authorities have said it appeared that at least one of two attackers who drove into the church compound on a motorcycle was killed in the blast.
A church security guard tried to prevent the motorbike from entering when the blast occurred, they said.
One eyewitness described hearing two “very strong” explosions and then seeing plumes of smoke at the scene.
Widodo said he “strongly condemned this act of terror”.
“Terrorism is a crime against humanity,” he said.
“I call on everyone to fight against terror and radicalism, which go against religious values.”
Amnesty International said the bombing showed “complete contempt” for human rights.
The explosion at the main Catholic cathedral in Makassar — a port city of about 1.5 million — happened just after congregants finished celebrating Palm Sunday, the first day of Holy Week, which commemorates Jesus’s entry into Jerusalem.
It comes a week before Easter.
In his mass for Palm Sunday, Pope Francis said he prayed for all the victims of violence “especially those of this morning’s attack in Indonesia, in front of the Cathedral of Makassar”.
Churches have been targeted in the past by extremists in Indonesia, the world’s biggest Muslim-majority nation and home to several religious minorities including Christians, Buddhists and Hindus.
Sunday’s attack follows the arrest in recent months of dozens of militants suspected of planning terror attacks, according to Indonesia’s counter-terror squad.
In 2018, a dozen people were killed when a family of suicide bombers blew themselves up at churches during Sunday services in Indonesia’s second-biggest city Surabaya.
The family — including two daughters aged nine and 12 — and another family of five, which carried out a suicide bombing on a police headquarters, all belonged to the same Koran study group.
They were also linked to local extremist network Jamaah Ansharut Daulah (JAD), which has pledged allegiance to Islamic State.
JAD, which has not claimed responsibility for Sunday’s attack, gained notoriety in 2016 for a gun and suicide bomb attack in the capital Jakarta that killed four civilians and four attackers — including one who blew himself up at a Starbucks outlet.
It was the first attack claimed by Islamic State in Southeast Asia.
Indonesia has long struggled with Islamist militancy and has suffered a series of attacks in the past two decades, including the 2002 Bali bombings which killed more than 200 people, mostly foreign tourists. The bombings were Indonesia’s deadliest terror attack.