Investigations into five terrorists arrested in Jakarta on Tuesday had led investigators to believe extremists were now more determined to destabilise the local economy than kill Westerners, they said.

The cell rounded up on Tuesday was planning to blow up Jakarta's main fuel depot and was connected to Abdullah Sunata, who was jailed in 2006 for protecting alleged Bali bomb mastermind Noordin Mohammad Top, they said.

'Their target has always been non-believers,' police Brigadier General Bambang Hendarto Danuri told reporters.

'But we have seen now that they are also targeting anti-terror agencies and those with links to the economy, not only the interests of the US and its allies.'

Sunata is believed to be a senior leader in the KOMPAK militant group that carried out attacks against Christians in the restive Poso and Ambon regions, and is serving seven years in prison for withholding information on Noordin.

Noordin has a one-billion-rupiah (S$153,549) price tag on his head for his alleged role in the 2002 Bali bombings and other attacks which have killed hundreds. He is believed to be hiding in Indonesia.

The five men arrested on Tuesday are alleged to have studied bomb making under Azahari Husin, an explosives expert and Noordin associate who was tracked down and shot at a house in Java in Nov, 2005.

Police said the men were also in possession of bomb-making material which showed 'significant progress' in design.

Investigators said on Wednesday they believed various Islamist extremist outfits had joined forces in Indonesia, including Noordin's militant wing of regional terror network Jemaah Islamiah. -- AFP