Investigators were sifting through two bomb-damaged luxury Indonesian hotels on Saturday, for clues to those behind suicide attacks that shattered four years of stability in the world's most populous Muslim nation, Reuters reported.
Although officials could not say who they believed was responsible for Friday's attacks, suspicion is pointing toward Jemaah Islamiah (JI), the radical militant Islamist group responsible for a string of deadly attacks that seemed to end in 2005.
"It has the signature of our 'friends'," said a retired Southeast Asian police officer now focused on counterterrorism in the region.
The bombers struck the JW Marriott and Ritz-Carlton, luxury hotels popular with businessmen and diplomats and considered to be among the most secure buildings in the capital.
Police told a news conference on Saturday that nine people were killed and 53 wounded in the blasts, revising a previous death toll after investigators had found it difficult to identify some victims from the remains.
"Of the dead, we believe that three we haven't yet identified include the suicide bombers," Foreign Minister Hassan Wirajuda said earlier.
The casualties included citizens of Indonesia, the United States, Australia, South Korea, the Netherlands, Italy, Britain, Canada, Norway, Japan and India.
The blasts are a severe blow for President Susilo Bambang Yudhoyono, who was re-elected earlier this month in a landslide victory on the back of strong growth in Southeast Asia's biggest economy.
After being rocked by a string of attacks against Westerners in the first part of the decade, Indonesia has been widely credited with successfully tackling militant groups.
Radical cleric Abu Bakar Bashir, who was alleged to have once headed JI, said the bombs were "a warning from God to Indonesia for not respecting God's law."
"Those who were involved were infidels or apostates, who wanted to impede the jihad in Indonesia," he said in a telephone text message to Reuters.
Questions will now be asked how supposedly tight security was so easily by-passed.
Police said the bombers had checked into the Marriott as paying guests on Wednesday and had assembled the bombs in their room. A third bomb was found and defused in a laptop computer bag on the 18th floor.
A police spokesman told reporters a metal detector had beeped when a bomb hidden inside a laptop bag passed through the scanner, but the bomber had said it was a laptop and the security guards had let him go through.
"Even as Indonesians are given due credit for all they have done preventing an attack for four years, they should also carefully examine what went wrong with security measures and seek a better understanding of the domestic network that supports terrorism," said the Heritage Foundation's Walter Lohman.
International reaction to the bombings has been swift.
U.S. President Barack Obama, who spent four years living in Jakarta as a child after his mother married an Indonesian, called Yudhoyono on Saturday and offered American help with the investigation, the White House said in a statement.
"The president and President Yudhoyono reaffirmed the close cooperation between the United States and Indonesia in countering extremism in Southeast Asia and around the world," the statement said.
Lohman said he was confident Indonesia could bounce back from the latest tragedy.
"Indonesia defines resiliency," he said in a commentary. "It will get past the July 17 bombings just as it got past the others." (Additional reporting by Telly Nathalia and Simon Cameron-Moore, and Ross Colvin in Washington; writing by David Fox; Editing by Sara Webb, Sophie Hares and Eric Beech)