The splintered radical Islamic Jemaah Islamiah is widely suspected of carrying out today's bombings in Jakarta, with one security report predicting only a day earlier that the group may be poised to strike.
No-one has claimed responsibility for the near-simultaneous blasts that ripped through the JW Marriott and the Ritz-Carlton hotels in the Indonesian capital today, killing nine people and wounding 42.
But security analysts say the militant Jemaah Islamiah, linked to al-Qa'ida and blamed for numerous attacks between 2002-2005 in Indonesia, including bombings on the island of Bali in 2002 that killed 202 people, is most likely responsible - fuelled by young hardliners and recently released members from prison.
The size of the hotel attacks supports the findings of an Australian security report on Thursday which said a splintered Jemaah Islamiah was probably not capable of "replicating mass casualty attacks".
"In a way this may be taken as a signal, after the Indonesian elections, a reminder that JI is still in the game," said security analyst Rory Medcalf from the Lowy Institute in Sydney.
Indonesian security forces have successfully prosecuted Jemaah Islamiah members in recent years, forcing the group to become dormant.
Founded around 1993, the goal of al-Qaeda-linked Jemaah Islamiah is the creation of an Islamic "super-state" spanning Indonesia, Malaysia, the southern Philippines, southern Thailand, Singapore and Brunei.
There have been no recent major bomb blasts while this month's presidential elections passed off peacefully, underscoring the progress made by the world's most populous Muslim nation since the chaos and violence that surrounded the downfall of ex-autocrat Suharto in the late 1990s.
"The advice that I have from the National Security Committee, and the agencies which service it, is that this is a terrorist attack," said Australian Prime Minister Kevin Rudd.
"In terms of the terrorist organisation and or individuals responsible for it that is currently the subject of work between the agencies," Rudd told a news conference in Sydney.
But the Australian security report titled "Jemaah Islamiah: A renewed struggle", says leadership tensions and recent prison releases raised the possibility that splinter groups might seek to re-energise the movement through violence.
It warned there was evidence that Jemaah Islamiah members released from prison were "gravitating towards hardline groups who continue to advocate al-Qa'ida-style attacks against Western targets". "These hardline groups continue to believe that the use of violence against the 'enemies of Islam' is justified under any circumstances," said the report by the Australian Strategic Policy Institute.
"Far from satisfied with the Bali bombings and other attacks now several years in the past, they dismissively refer to many senior JI members as NATO - No Action, Talk Only," it said.
"The hardline group is fully supported by a group of young, dedicated individuals who share a deep commitment to the cause, advocating al-Qaeda-style attacks that directly target Westerners and Western interests if the time is 'ripe' for them."
It highlighted the fact that several senior Jemaah Islamiah leaders, including Noordin Top, head of its most violent group, remained at large.
"The likelihood is that it was Noordin Top's cell that was responsible because the judgment was that they were capable of doing small devices, but not vehicle bombs," said Clive Williams at the Strategic and Defence Studies Centre in Canberra.
"From what I can see so far the devices at the Marriott and Ritz-Carlton seem to be smaller devices that were either left there or detonated by suicide bombers, but it is more likely they were left there," Williams told Reuters.
Theo Sambuaga, head of a parliamentary commission in charge of security affairs, said a suicide bomber was involved in at least one of the blasts.
Some analysts are investigating whether some Jemaah Islamiah members are rekindling links with jihadists in Pakistan, raising the question of whether the Jakarta bombings were a purely domestic attack or whether they may have been directed or co-ordinated from abroad.
Williams said the bombings were probably domestic and may have had a dual purpose - to warn off Westerners and undermine the Indonesian government, but also bolster recruitment and strengthen the splintered group.
"I think it is more a matter of showing that they can still do things. It might be related to recruitment, pressure within the cell for them to do something as its very hard to hold a cell together when you don't do anything.
"...I suspect it is only a very small element of JI that is responsible for this."Reuse content