Members of a single family have carried out a suicide bombing at the police headquarters in Indonesia days after another family, with whom they were friends, launched co-ordinated suicide blasts on churches in the same city.
CCTV footage of the latest attack showed the militants, who included an eight-year-old girl, in a car and on two motorcycles approaching a security checkpoint near the police station in the city of Surabaya.
An explosion was then triggered from one of the motorbikes, which had at least two people on it.
National police chief Tito Karnavian said the girl, who was with two of the four attackers, was thrown off the motorcycle by the blast and survived, while the others died.
Four officers and six civilians were wounded, authorities said.
Mr Karnavian added that the police headquarters bombers and those who targeted churches were friends, as were another family whose homemade bombs exploded in their apartment on Sunday night, killing them all. The latter blast took place at a flat in Sidoarjo, a town bordering Surabaya, and was presumably a result of preparations for yet more deadly attacks going awry.
The first spate of attacks killed 13 people at churches in the city on Sunday.
Police said the family responsible had returned to Indonesia from Syria, and included two girls aged nine and 12.
Mr Karnavian said the father drove a bomb-laden car into the city's Pentecostal church. The mother, with her two daughters, attacked the Christian Church of Diponegoro, he said. Based on their remains, Mr Karnavian said the mother and daughters were all wearing explosives around their waists.
The sons aged 16 and 18 rode a motorcycle onto the grounds of the Santa Maria Church and detonated their explosives there.
All six members of the family died.
Isis claimed responsibility for the church attacks in a statement carried by its Aamaq news agency.
It did not mention anything about families or children taking part and said there were only three attackers.
The flurry of attacks have raised concerns that previously beaten down militant networks in the world's most populous Muslim-majority nation have been reinvigorated by the return of some of the estimated 1,100 Indonesians who went to fight with the Islamic State (IS) group in Syria.
Experts have been warning for several years that when those fighters returned, they could pose a significant threat.
Indonesia's president Joko Widodo condemned the attacks as "barbaric" and vowed that authorities would root out and "destroy" Islamic militant networks.
Agencies contributed to this report
