All six family members died in the coordinated bombings, which wounded at least 40 people, police said, including on-duty police officers. The Islamic State militant group asserted responsibility for the attacks, according to the SITE Intelligence Group.
President Joko Widodo visited the scene of the attacks. He said the “cowardly actions” of the attackers were “very barbaric and beyond the limit of humanity,” the Associated Press reported.
Indonesia, the world’s most populous Muslim nation, has struggled with Islamist terrorism and violence against its Christian minority in the past two decades. Sunday’s bombings are the worst attacks on churches there since a Christmas Eve bombing in 2000 killed 15 people and wounded 100.
National police chief Tito Karnavian said the family had returned to Indonesia from Syria, according to the AP. Militants there have retreated from territory lost in recent months to U.S.-backed offensives and gains by the Syrian government. Police said the family was among 500 Indonesians who have returned from Syria and who may have ties to the Islamic State, Reuters reported.
For years, analysts have warned that Indonesia would develop into a militant outpost in Southeast Asia as insurgencies in the Middle East provide battlefield experience harnessed by foreign fighters after they return home.
The shattered remnants of buildings littered the streets as emergency personnel treated survivors of the church bombings in the sprawling, densely packed city.
The first bombing occurred at the Santa Maria Roman Catholic Church in between two Masses.
“I saw two men riding a motorbike force their way into the churchyard. One was wearing black pants and one with a backpack,” a merchant known only as Samsia told the AP. She said she was thrown several feet by the concussive force of the blast.
Surveillance video purportedly shows one of the bombers on a bike bank sharply to the left. A cloud of smoke billows from the explosion off-frame.
Within minutes, the mother and her two daughters targeted the Christian Church of Diponegoro.
“At first officers blocked them in front of the churchyard, but the woman ignored them and forced her way inside. Suddenly she hugged a civilian, then [the bomb] exploded,” said Antonius, a security guard who identified himself to the AP using one name.
Around that time, the father rammed his explosives-packed SUV into the Pantekosta Church gate, Reuters reported. Police said unexploded bombs found at two of the churches were safely detonated by authorities.
The Indonesian Church Association condemned the attacks, as did the country’s two largest Muslim organizations, Nahdlatul Ulama and Muhammadiyah, the AP reported.
National police spokesman Setyo Wasisto said police killed four suspected militants and arrested two early Sunday in West Java, though it was not clear whether that activity was connected to the church bombings, the AP reported.
Wasisto said they were members of Jamaah Ansharut Daulah, a network of about two dozen terrorism groups affiliated with the Islamic State, according to the State Department.
Officials raised the possibility that the Sunday bombings were a response to the bloody end of a prison riot and two-day standoff by Islamist terrorism suspects detained near Jakarta. At least five guards and one detainee were killed after the hostage situation ended in a police raid Thursday. The Islamic State claimed responsibility for the uprising.