Some churches have been attacked by suicide bombers during Sunday service, sparking serious commotion.
The attacks were carried out within minutes of each other
According to a BBC report, suicide bombers have attacked three churches in Indonesia's second-largest city Surabaya, killing at least nine people during Sunday service.
Police say 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.
Firefighters attended the scene at the Pentecost Church Central Surabaya (GPPS)
The bombings took place around 07:30 local time (00:30 GMT). Officials said they foiled an attack against a fourth church.
The country's intelligence agency said the attacks were most likely to have been carried out by an Islamic State-inspired group, Jemaah Ansharut Daulah.
Earlier this month, members of the Indonesian 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.
Over 90 per cent of Indonesians are Muslim, but there are also significant populations of Christians, Hindus and Buddhists.