A group of men armed with samurai swords targeted a police station in Indonesia on Wednesday.
The Riau Provincial Police have managed to thwart an attempt to conduct a terror attack by shooting dead four terror suspects, according to the Indonesian Police (Polri).
Just hours after the church bombings, a further three people in another family were killed and two wounded when another bomb exploded at an apartment complex about 30km from Surabaya.
Media said one attacker may have had a bomb strapped to his body but police did not immediately confirm the reports.
Police said three of the Pekanbaru attackers were Riau residents aged between 26 and 42.
A fifth man, who drove the vehicle, was arrested while attempting to escape. The multiple suicide bombings were carried out by families who had even included their young children. The terrorist group intends to establish an Islamic state in Indonesia.
Police suspect the fathers of both families belonged to the group Jamaah Ansharut Dauluh, which is known to support the Islamic State militant group.
"They all pledged allegiance to [ISIS leader] Abu Bakr al-Baghdadi", Wasisto said, the Jakarta Post reported.
Its worst-ever attack was the 2002 Bali bombings that killed more than 200 people, including locals and foreign tourists.
On May 14, the Surabaya police headquarters was also attacked by a suicide bomber.
This week's violence puts pressure on politicians to pass a stalled security law that would give police more power to take pre-emptive action against people suspected of planning terrorist attacks.
Police shot a militant and arrested at least 13 others in a series of raids following the Surabaya attack.
One local journalist at the scene sustained minor injuries in the attack, police said.