Suicide bombers have attacked three churches in Indonesia’s second-largest city Surabaya, killing at least 11 people.
Around 40 others were injured in the attacks, which occurred within minutes of each other. No group has so far said it carried them out.
TV pictures showed debris scattered around the entrance of one church.
Indonesia, the most populous Muslim-majority country, has seen a resurgence of Islamist militancy in recent months.
More than 90% of Indonesians are Muslim, but there are also significant populations of Christians, Hindus and Buddhists.
The attack is the deadliest since 2005, when three suicide bombings on the resort island of Bali killed 20 people.
The first explosion took place between services at the Santa Maria Catholic Church around 07:30 local time (00:30 GMT). Inspector General Machfud Arifin told CNN Indonesia that a motorbike was used in the attack.
According to Reuters, the second bombing targeted the cark park of a Pentecostal church. Images of the scene showed a number of burnt motorcycles.
Unconfirmed eyewitness reports say that the third attack was carried out by one or more veiled women who entered a church with children.
Officials reportedly foiled attacks against other churches.
So far there has been no claim of responsibility for the attacks.
But Wawan Purwanto, of Indonesia’s intelligence agency, said the Islamic State-inspired group, Jemaah Ansharut Daulah (JAD), was suspected to be behind them.
He added that the bombings were likely to be linked to an incident earlier this month, when five members of the security forces were killed during a 36-hour standoff with militant Islamist prisoners at a high security prison on the outskirts of the capital Jakarta.
Separately, police said they had killed four suspected members of JAD in Cianjur, West Java.
Christian leaders urged calm. “We don’t need to be afraid when facing terror threats. We must leave it completely to the government to handle,” the head of the Indonesian Communion of Churches said in a statement on Sunday quoted by The Jakarta Post.
Indonesia’s Foreign Minister Retno Marsudi condemned the attack and sent her condolences to the victims and their families.
Strongly condemn the terrorist attack in Surabaya – Ret
We will not back down in the fight against terrorism
— Menteri Luar Negeri Republik Indonesia (@Menlu_RI) May 13, 2018
Witnesses there described three consecutive blasts which shattered church windows and a metal roof canopy, and burned cars in the adjacent carpark. The bomb was suspected to be planted in one of the cars parked outside the church.
President Joko Widodo, who rushed to the city yesterday, described the attacks as “truly savage and beyond tolerable” and said he there were “no words to express the sorrow we feel for the loss of lives”.
“This is a crime against humanity and has nothing to do with religion. We must unite to fight against terrorism.”
The attacks come several days after five Indonesian police officers and a prisoner were killed in clashes that saw Islamist inmates take a guard hostage at a high-security jail on the outskirts of Jakarta.
The Islamic State (IS) group claimed responsibility for that incident although police rejected its involvement.
Prime Minister Malcolm Turnbull and Foreign Minister Julie Bishop issued a joint statement saying Australia condemned the “cowardly terrorist attacks” on the churches as well as wednesday’s attacks at the Indonesian Police Mobile Brigade Headquarters.
“We stand in solidarity with the Government of Indonesia….(and) offer our sincere condolences to the family and friends of those killed and injured,” it said.
“Australia remains committed to our close security partnership with Indonesia to combat terrorism, including cooperation between law enforcement and security agencies.”
Indonesia’s 260 million people includes significant numbers of minority Christians, Hindus and Buddhists but there are concerns over rising sectarian intolerance and militancy.
Indonesian police shot and wounded a man who attacked a church congregation in the town of Sleman with a sword during a Sunday mass in February.
The radical Islamist, who had wanted to fight with the Islamic State group in Syria, injured four people.