Authorities said Azahari bin Husin and Noordin Top, both Malaysians, are key members of Jemaah Islamiyah, an al-Qaeda-linked group blamed for the bombing that killed nine people and injured more than 170 last Thursday in Jakarta.
While a massive manhunt by Indonesian police for Azahari and Noordin gets underway, officials warn of more possible suicide attacks on Western interests in Indonesia.
The Associated Press reported that Azahari is a British-trained engineer who allegedly taught Islamic militants in Mindanao and Afghanistan how to make bombs.
Noordin, meanwhile, is a university graduate and an explosives expert.
"We are still facing a terrorist threat, especially from Azahari and Noordin Top," Indonesia’s national police chief, Gen. Dai Bachtiar, said Sunday. "We are hunting them down."
Jemaah Islamiyah (JI) has been linked by regional intelligence officials to the secessionist Moro Islamic Liberation Front (MILF).
The MILF, which has been fighting a decades-long rebellion to establish an independent Islamic state in Mindanao, denies having ties with Jemaah Islamiyah, which reportedly operated training camps inside MILF jungle bases in the volatile south.
No such facilities were reported following a massive Philippine military offensive in 2000 against the MILF. However, Jemaah Islamiyah was believed to be responsible for a bomb attack on the Philippine ambassador’s residence in Jakarta that year, seriously wounding then ambassador Leonides Caday.
A top Indonesian police official, who spoke on condition of anonymity, said authorities believed Azahari and Noordin were still in Indonesia, probably near Jakarta.
He said Azahari and Noordin easily find shelter with Islamic extremists in Indonesia, the world’s most populous Muslim nation.
Azahari and Noordin have reportedly eluded capture at least five times in the past year.
Indonesia has endured a series of terror attacks since 1999, all of them blamed on Jemaah Islamiyah. The worst were bombings that killed 202 people on the resort island of Bali two years ago and a suicide attack on Jakarta’s JW Marriott Hotel that killed 12 last year.
Australian Prime Minister John Howard revealed that intelligence gathered by the Indonesians and Australians indicated that the "number of Jemaah Islamiyah operatives is sufficiently large to support the fear there could be another attack."
Despite the lethal embassy bombing — the third major attack in Indonesia in two years — Jakarta seemed to have acquired an ability to quickly return to some semblance of normalcy, Time noted in an article.
"People are getting used to the idea that this sort of thing is going to happen. They know who is behind it and they know that the police are doing a pretty good job of tracking them down. It’s like living in London when the IRA was bombing there, or in Spain with the ETA attacks," Hans Vriens, head of the Jakarta office of the political consultancy Apco, told Time.
The biggest impact of the bombings may be political, wrote Time.
Indonesian President Megawati Sukarnoputri is gunning for reelection in runoff polls on Sept. 20 and Australia will hold general elections next month.
"But it remains unclear whether the bombers aimed to influence voters in either Australia or Indonesia — or whether they were simply reminding the world of their existence," according to Time.
They also had planned to attack the opening ceremony of an anti-terrorism center in Semarang in July, but the operation was canceled because of tight security, Bachtiar said. Megawati and Australian Justice Minister Chris Ellison attended the ceremony.
An Islamic website posted a message claiming Jemaah Islamiyah attacked the Australian Embassy because of its support for the US-led war in Iraq.
Security has been stepped up in Jakarta since Thursday, with embassies adding guards and barriers. Some roads have been closed.
The Australian Embassy warned that more attacks "could not be ruled out" and urged Australians to avoid the area around the mission, including the huge Rasuna apartment complex where a number of Westerners live. The US Embassy e-mailed similar warnings to Americans.
"We’ve received reports by Americans that there are further threats in that area," Australian Ambassador David Ritchie told reporters. "I would urge residents of that complex to ... take appropriate action, and that could well involve leaving."
Ritchie said embassy staff would return to work Tuesday, but the mission would remain closed to the public.
Over the weekend investigators re-enacted the embassy bombing at the scene, a routine practice in Indonesian criminal cases. Security camera footage during the attack showed a white delivery van swerve past a police truck outside the heavily fortified embassy and then explode.
Police said they recovered traces of TNT and sulfur — chemicals used in the embassy bomb — from a West Jakarta house rented by Azahari and Noordin. Newspapers quoted neighbors as saying four men rented the house for five days and were seen loading boxes into a pickup truck.