Indonesian police say the suicide bombers who attacked three churches in Surabaya were all members of one family.
At least 13 people were killed and more than 40 injured when the group targeted Sunday mass congregations in the country’s second-largest city.
Indonesia’s police chief Tito Karnavian said the family had been in Syria where the Islamic State group until recently controlled a large swath of the country.
He said the family’s father carried out one of the attacks by exploding a car bomb, while the man’s two sons, aged 18 and 16, used a motorbike in their attack. Their mother carried out another attack with her two children, aged 12 and nine.
Indonesian President Joko Widodo visited the sites and described the attacks as “cowardly actions” that were “very barbaric and beyond the limit of humanity”.
The first attack, at the Santa Maria Roman Catholic Church, killed four people, including one or more bombers, police spokesman Frans Barung Mangera told reporters at the scene.
A street merchant outside the church said she was blown several metres away by the powerful blast.
“I saw two men riding a motorbike forced their way into the churchyard. One was wearing black pants and one with a backpack,” said Samsia, who uses a single name.
“Soon after that the explosion happened.”
Shattered glass and chunks of concrete littered the entrance of the church, which was sealed off by heavily armed police.
Rescue personnel were treating victims on a nearby field while officers were inspecting wrecked motorcycles in the parking lot that were burned in the explosion.
Minutes after the first, there was a second explosion at the Christian Church of Diponegoro that killed two people.
A witness described the woman with children, saying she was carrying two bags at the Diponegoro church.
“At first officers blocked them in front of the churchyard but the woman ignored them and forced her way inside. Suddenly [the bomb] exploded,” said a civilian guard named Antonius.
Another two people died in a third attack at the city’s Pantekosta Church, Mr Mangera said.
One other died in a hospital, he said.