13 May, 2018
The police said the blasts all occurred within 10 minutes of each other, with the first around 7.30 am local time (6 am Indian Standard Time), AFP reported.
The first attack struck a Sunday Mass at the Santa Maria Roman Catholic Church, killing three people, police spokesman Frans Barung Mangera told reporters at the scene.
This is a developing story.
The attacks in the predominantly Muslim country came days after police ended a riot and hostage-taking at a detention center near Jakarta that left five dead and five injured.
Particles are seen exterior Santa Maria church the place an explosion went off in Surabaya, East Java, Indonesia, Could 13, 2018.
Another two people died in a third attack at the city's Pantekosta Church, Mr Mangera said.More news: Elon Musk's LA tunnel is nearly finished - and he's offering fre
Some of the suicide bombers were on motorcycles, while one of the attacks was carried out by a suicide bomber disguised as a churchgoer. No one has yet claimed responsibility.
"They have trained in order to attack police", Mr Wasisto said, identifying the militants as members of Jemaah Anshorut Daulah.
Almost 90 percent of Indonesia's 260 million people are Muslim, but there are significant numbers of Christians, Hindus and Buddhists.
Police said at least five suicide bombers were involved, including at least one on a motorcycle and a woman who had two children with her, according to The Associated Press.
Hundreds of Indonesians have flocked to fight with IS, sparking fears that extremist outfits back home could get a new lease on life. The incident is estimated to be the deadliest attack in recent years to hit the world's biggest Muslim-majority nation.
Sunday's bombings had the highest death toll since nine people were killed in 2009 attacks on two luxury hotels in Jakarta.