Jakarta. The National Police said on Tuesday (20/12) that they have arrested three people over a suspected plot to carry out a suicide bomb attack in an undisclosed location outside Java.

Two men were arrested in Solo, Central Java, on Sunday on suspicion that they made explosives to be carried by a female accomplice, National Police spokesman Chief Comr. Martinus Sitompul said.

A suspected female suicide bomber was arrested in Purworejo, also in Central Java, last Thursday.

"The group was planning to carry out an attack outside Java," Martinus said. He declined to elaborate and said police would hold a news briefing later this week.

The three are linked to a group police arrested earlier this month for planning an attack at the changing of the guard at the Presidential Palace in Central Jakarta, he added.

In both cases, police suspect the groups planned to use a female suicide bomber, a new tactic for attacks in Indonesia.

The suspects held over the planned Jakarta attack had been communicating with and received money from Bahrun Naim, an Indonesian militant known to be fighting with the Islamic State movement in Syria, police have said.

The police are currently interrogating 14 suspects related to the planned Jakarta bombing and the plot outside Java, Martinus said.

Security is usually stepped up in Indonesia at this time of year, following attacks in previous years during Christmas and New Year celebrations.

A bomb squad detonated an unattended backpack with a sign saying "bomb" in Ubud, Bali, earlier on Tuesday. Bali Police spokesman Made Sudana said there was no bomb threat and it contained fireworks. He added that the backpack belonged to a Dutch man who had lost it.

Bali has suffered two major attacks, including nightclub bombings in 2002 that killed 202 people, and suicide attacks in 2005 that killed 20.

Reuters