JAKARTA - INDONESIAN police are looking at possible links between Friday's deadly twin bombings on luxury hotels in downtown Jakarta and wanted Malaysian-born Islamic extremist Noordin Mohammed Top.

Two bombs tore through a restaurant and carpark in the Ritz Carlton and JW Marriott hotels around 8.00 am (9.00 am Singapore time) as guests were having breakfast, killing at least nine people and wounding 40 others.

A senior official said police had found a third, unexploded bomb in a room at the Marriott described as a 'control centre' for the attacks, the deadliest in Indonesia since 2005.

The room contained explosive chemicals and bomb-making materials, he said, a likely treasure trove for Indonesian police to examine along with their Australian and US counterparts.

'The control centre was a room at the JW Marriott, room number 1808, where anti-terror police found explosive materials and an unexploded bomb,' Djali Yusuf, a senior advisor to President Susilo Bambang Yudhoyono, told AFP.

The bomb was defused as police searched the hotel following the bombing in its basement, which killed seven people. Twelve people died in a bombing of the Marriott in 2003 which was blamed on the Jemaah Islamiyah terror network.

Police have not said who they believe was responsible for the attacks and no group has claimed responsibility, but senior sources in the counter-terrorism unit said they bore all the hallmarks of master bombmaker Noordin.

The former accountant is the chief ideologue of the most violent wing of Jemaah Islamiyah and is wanted for his alleged role in several attacks including the bombings that killed 202 people in Bali in 2002.

'There must be a link with Noordin Top. There's a big possibility. But we still need to investigate how far he is involved,' a counter-terrorism officer said, requesting anonymity due to the sensitive nature of the investigation.

Unconfirmed reports in the Indonesian media earlier this week said police had raided an Islamic school in Cilacap, Central Java, in search of Noordin but the extremist was nowhere to be found.

'If it was a suicide bombing, then it's certainly a possibility that this was done by Noordin's network,' International Crisis Group think-tank terrorism analyst Sidney Jones said.

'Noordin is no longer acting in the name of JI. He's a splinter of JI,' she said.

Police said the bombs used in Friday's attacks were homemade and they suspected at least one - the device used in the carpark basement of the Marriott - was triggered by a suicide bomber.

'This should be a suicide bomber because there is a victim with his head cut off,' the counter-terrorism source said.

Jakarta police chief Wahyono said the bombs were similar in both attacks and were not particularly powerful.

He said the suspected suicide bomber at the Marriott had 'disguised himself as a guest'.

Since the last major terror bombing in the mainly Muslim country, in 2005, Indonesian police have won praise for rounding up hundreds of JI militants and preventing a number of attacks.

Three of the extremists convicted of the 2002 bombings on the resort island of Bali were executed last year despite protests from their hardline supporters, who represent a tiny minority of Indonesia's 210 million Muslims.

Al-Qaeda-inspired extremists sympathetic to Jemaah Islamiyah vowed to launch a wave of attacks in revenge for the executions of their 'martyrs'. -- AFP