On Sunday, coordinated suicide bombings at three churches carried out by a family of six claimed 12 lives in Surabaya, the country's second-largest city.
Editor's note: An earlier version of this article stated that at least three men had attacked the Riau Police headquarters.
The suicide bombings, involving families with young children, and an explosion at an apartment where militants were suspected to have been constructing bombs have left around 30 people dead, including 13 suspected perpetrators, police said.
Indonesian policemen examine a vehicle used by attackers outside the police headquarter in Pekanbaru, Riau. "We encourage people to take responsibility for their own safety".
Last year, a suicide bombing at a bus station in Jakarta killed three police officers.
The next day, members of another family blew themselves up at a police station in the city, wounding 10.
The families have been linked to the local chapter of Indonesian extremist network Jamaah Ansharut Daulah (JAD), which police said was behind the attacks.