Indonesia’s police chief said that the suicide attack outside Surabaya’s police headquarters in the centre of the city on Monday morning was carried out by a family of five, including an eight-year-old girl, who survived the attack.
CCTV footage showed two motorcycles approaching the gate of the police station before the explosion took place.
Ten people were wounded in the attack, including police officers, authorities said.
Indonesia’s President Joko Widodo condemned the latest bombing, calling it “cowardly, undignified and inhumane”.
“There will be no compromise in taking action on the ground to stop terrorism,” he told reporters in Jakarta, Indonesia’s capital, on Monday.
No group has so far claimed responsibility for the attack.
Earlier in the day, a couple and a child were killed in their apartment when home-made bombs accidentally exploded in Sidoarjo, about 30km from Surabaya.
At least 23 people have now died, including the attackers, and dozens more injured in the Southeast Asian nation in the past 24 hours.
The fifth and latest bomb blast comes after separate suicide attacks by one family on three churches sent shockwaves across Surabaya, about 800km west of Indonesia’s capital, Jakarta.
A spokesperson for the country’s intelligence agency said Sunday’s bombings were suspected to have been carried out by an ISIL-inspired group, Jemaah Ansharut Daulah (JAD).
Al Jazeera’s Step Vaessen, reporting from Surabaya, said the whole country is now on “high alert”.
“There are a lot of hoaxes going on social media about possible bomb attacks in other cities as well,” she said.
“Suspicious packages are being thrown, a lot of information is also untrue, which is going around social media, so people are really shivering here at the moment.”