The attack was the deadliest in Indonesia since January 2016, when eight people were killed, four of them attackers, after suicide bombers and gunmen attacked the capital. '
"We must continue to keep calm (and) keep cool. Because ... we Muslims are preparing to enter the month of Ramadan for fasting," President Joko Widodo said in a statement.
Authorities in the world's biggest Muslim-majority nation are increasingly worried about a surge in radicalism, driven in part by a new generation of militants inspired by Islamic State.
It was "highly likely" an Islamic State-linked group was behind Wednesday's attack, National Police spokesman Awi Setyono said.
"There's a link, but we're still studying whether it's an international network," Setyono said.
Earlier, he told reporters that police were investigating whether the attackers had direct orders from Syria or elsewhere.
A law enforcement source, who spoke on condition of anonymity, said they may have been linked to Jemaah Ansharut Daulah, an umbrella organization on a U.S. State Department "terrorist" list that is estimated to have drawn hundreds of Islamic State sympathizers in Indonesia.
Indonesia has suffered a series of mostly low-level attacks by Islamic State sympathizers in the past 17 months
Islamic Terrorism has gone too far, and I don't think 'talks' or reasoning their actions with them are going to change anything...How do we get them to stop attacking and killing people of the World, and be honest at the same time that we do not want to become a Sunni or Shiite, or spin-off believer, and do not want Sharia Law in our lives?
Remember these are people of a different value system than ours---they believe they are doing the right thing. I don't know what we should do?