The strike was launched just weeks after Indonesia issued a heightened alert and arrested several suspected militants, some of them from IS-linked cells.
The Soufan Group, a New York-based security consultancy, says that of the 500-700 Indonesians who travelled abroad to join IS's self-proclaimed caliphate across swathes of Syria and Iraq, scores have since returned.
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Indonesia, the world's most populous Muslim-majority nation, launched a crackdown that neutered the networks, and attacks in recent years have mostly been low-level and have targeted domestic security forces.
More recently, the country has banned support for IS and its ideology, but experts worry that Indonesian laws are not adequate for tackling the new threat and that the region is failing to pull together.
“The governments in this region must work together to prevent the creation of a satellite of the caliphate because if such a satellite is declared, the threat in Southeast Asia will grow,” said regional terrorism expert Rohan Gunaratna.
Jakarta - A “Paris-style” suicide strike on the Indonesian capital on Thursday confirmed Southeast Asian governments' worst fears - that citizens returning from fighting alongside the Islamic State group in the Middle East could launch attacks at home.
Regional nations have been warning for months of the possibility of attack, mirroring concerns expressed by European authorities fearful of the intentions of people returning home from conflict.
The blasts and gunfire that rocked Jakarta came after six years of relative calm, following a government crackdown that weakened the country's most dangerous homegrown Islamic networks.
“We know that (IS) has the desire to declare a province in this region and there are groups in this region...
that have pledged allegiance to (IS),” said Kumar Ramakrishna, an expert on southeast Asian militant groups at Nanyang Technological University in Singapore.
“The threat of returning Southeast Asian fighters radicalised in the Iraq/Syria region (is) also another factor of concern, together with the possibility of self-radicalised lone wolves appearing in the scene.” Thursday's attacks left five attackers and two civilians, including a Westerner, dead and 19 others wounded.