The raid came soon after Indonesian police had said they were interrogating 14 suspects after a series of arrests relating to planned suicide attacks in the capital, Jakarta, and elsewhere.
“During the raid, we tried to be careful but they threw something from inside the house and it was a bomb but it did not explode. Then they fired from inside,” national police spokesman Rikwanto, who like many Indonesians uses only one name, told Metro TV.
Indonesian television footage showed a bomb squad officer wearing a blast-resistant suit entering the house in South Tangerang, as locals watched from behind a police tape.
“Inside the house we found a bigger bomb and now we are investigating it to try to detonate it,” Rikwanto said.
He said one suspect had been found alive.
Ayi Supardan, a senior officer from South Tangerang police, said that, after initial interrogation of the suspect who was found alive, it appeared there was a plan to use the larger bomb at the end of the year.
There was no indication of any possible target.
Planned suicide attacks
Earlier on Tuesday, Indonesian police said they were interrogating 14 suspects related to planned suicide attacks in Jakarta and outside the most populous island of Java.
The suspects held over the planned Jakarta attack had been communicating with, and received money from, Bahrun Naim, an Indonesian militant known to be fighting with the Islamic State militant group in Syria.
Two men were arrested in the Central Java city of Solo on Sunday on suspicion they made explosives to be carried by a female accomplice, said Martinus Sitompul, a spokesman for the national police.
A suspected female suicide bomber had been arrested in Purworejo, also in Central Java, last Thursday, he said.
“The group was planning to carry out an attack outside Java,” Sitompul said. He declined to elaborate and said police would hold a news briefing later this week.
The three were linked to a group police arrested earlier this month for planning an attack at the changing of the guard at Jakarta’s presidential palace, he added.
In both cases, police suspect the groups planned to use a female suicide bomber, a new tactic for attacks in Indonesia.
Security is usually stepped up in Indonesia at this time of year, following attacks in previous years during Christmas and New Year celebrations.
Earlier on Tuesday, a bomb squad on the Indonesian island of Bali detonated an unattended backpack in the city of Ubud with a sign saying “bomb”. Bali police spokesman Made Sudana said there was no bomb threat and it contained fireworks, adding the backpack belonged to a Dutch man who had lost it.
Bali has suffered two major attacks including nightclub bombings in 2002 that killed 202 people, and suicide attacks in 2005 that killed 20.