A suicide bombing at a police headquarters in the Indonesian city of Surabaya on Monday was carried out by a family of five riding on two motorbikes, police say.
It came after another family carried out bomb attacks on three churches on Sunday, in an attack claimed by the Islamic State (IS) group.
An eight-year-old girl survived the latest attack, police say.
Indonesia is the world’s most populous Muslim-majority country.
The archipelago, home to 260 million people, has seen a resurgence of Islamist militancy in recent months, and the attacks in Surabaya have raised concerns about the potency of jihadist networks.
Video footage of the latest attack on the police headquarters shows two motorbikes approaching a checkpoint just before the blast. Six civilians and four police officers were injured, authorities said.
What preceded the latest attack?
Indonesia was on high alert after bombings on Sunday by a single family targeted three churches in Surabaya.
A mother and two daughters, aged nine and 12, blew themselves up at Diponegoro Indonesian Christian Church, while the father and two sons targeted two others.
In the first attack, the sons – aged 16 and 18 – rode motorcycles into Santa Maria Catholic Church at around 07:30 local time (00:30 GMT) and detonated explosives they were carrying.
After reportedly dropping his wife and daughters off to carry out their attack, the father, Dita Oepriarto, drove his own bomb-laden car into the grounds of Surabaya Centre Pentecostal Church, police said.
Authorities originally said the family of six were among hundreds of Indonesians who had returned from conflict-hit Syria but have since said that the family did not actually travel there.
The coordinated attacks killed 13 people and injured more than 40. They were the deadliest bombings in Indonesia in more than a decade.
Police say Oepriarto was the head of local branch of Jemaah Ansharut Daulah (JAD), an Indonesian IS-inspired network.
Separately on Sunday:
- A bomb exploded at an apartment complex in Surabaya, killing three members of a family who police said may have been planning an attack
- Police said they killed four suspected members of JAD in Cianjur, in West Java province, and arrested two others
How has the government reacted?
President Joko Widodo has described the attacks as “cowardly, undignified and inhumane”.
“There will be no compromise in taking action on the ground to stop terrorism,” he said.
Authorities on Monday said police, backed by military forces, would increase security across the country.
What is the history of militancy in Indonesia?
The South East Asian country has long struggled with Islamist militancy. Its worst ever terror attack was in Bali in 2002, when 202 people – mostly foreigners – were killed in an attack on a tourist nightlife district.
That attack was carried out by the Jemaah Islamiah (JI) militant network.
But recent years have seen a number of attacks claimed by IS:
- Four civilians and four attackers were killed in a series of explosions and shootings in central Jakarta in January 2016; the first attack claimed by the group
- In February this year, a number of people were injured in a sword attack at a church in Sleman, Yogyakarta. Police said that the attacker had previously tried to join IS in Syria