Authorities said several accounts had been found on social networking website Facebook expressing support for Thursday’s attack in Jakarta’s commercial district, which killed seven people including five militants, and injured around 30 others.
The brazenness of the assault, which lasted several hours, suggested a new brand of militancy in a country where low-level strikes on police are common.
“We are monitoring many websites and public complaints about this,” said Ismail Cawidu, a public relations official at the communications ministry.
The government had also sent letters to social media companies such as Facebook, Twitter and Telegram requesting that radical material be immediately blocked or taken down, Cawidu said.
The alleged mastermind behind this week’s attack, an Indonesian citizen fighting with IS in Syria, is believed to have used social media extensively to share his beliefs about Islamic State and communicate with contacts in Indonesia using blog posts and mobile messaging apps.
Police said late on Friday that two of the attackers had been identified as raids continued across the country to track down any other militants in the networks they belonged to.
Authorities believe there are up to 1,000 IS sympathisers in Indonesia.