The United States has designated the Islamic State-linked Indonesian extremist network that carried out a deadly attack in Jakarta last year as a terrorist organization.
The State Department said Tuesday that Jamaah Ansharut Daulah (JAD) is "a terrorist group based in Indonesia that was formed in 2015 and is composed of almost two dozen Indonesian extremist groups" who are followers of IS.
The US also announced sanctions against four militants as part of efforts to cut off IS's access to the international financial system.
US officials said militants from JAD carried out a gun and suicide attack in the Indonesian capital in January last year that left four civilians and four attackers dead in the first IS attack in Southeast Asia.
The attack was financially supported by an IS militant in Syria, they said.
The State Department said the consequences of being designated a terrorist group included a ban on US citizens engaging in business with JAD, and the freezing of any property linked to the group in America.
JAD has been connected to a series of other plots in Indonesia, including a firebomb attack on a church that killed a toddler and a plan to launch a Christmas-time suicide bombing which was foiled when the militants planning the attack were killed.
Among the four militants to be sanctioned are two Indonesians.
Bahrumsyah is an Indonesian fighting with IS in Syria who is believed to lead a Southeast Asian unit of radicals, and who has sought to order attacks back home and transferred funds to militants.
The other Indonesian militant is Aman Abdurrahman, a jailed radical who authorized the Jakarta attack and is considered the de facto leader of all IS supporters in Indonesia, according to US officials.
Despite being in prison since 2010, he has recruited militants to join IS, is thought to have been in communication with leaders of the jihadist group, and is the main translator for IS propaganda in Indonesia.
The Treasury also slapped sanctions on two Australians -- Neil Christopher Prakash, IS's most senior Australian recruiter, and Khaled Sharrouf, who has appeared in photographs holding the severed heads of people executed by the jihadists.
Indonesia, the world's most populous Muslim-majority country, has long struggled with Islamic militancy and has been hit by a series of attacks in the past 15 years, including the 2002 Bali bombing that left 202 people dead.
A crackdown had weakened the most dangerous networks, but fears have been growing of a resurgence in militancy after hundreds of Indonesians flocked to the Middle East in recent years to join IS.