Investigators found ammunition and explosives in the house Wahyu used as his base of operation. The explosive material they discovered was destined for a terrorist attack set to take place this afternoon against a fuel depot in Plumpang.

Had it been carried out, both the capital and the whole island of Java would have been thrown into chaos.

Some Indonesian security experts also believe that Kalimantan and Sulawesi Islands would have also been seriously affected by the lack of fuel produced in Petramina’s Plumpang plant.

According to police, the terrorists had been planning the attack for quite some time, hiding out in Kelapa Gading district, an area north of Jakarta, just a few kilometres from the target. But agents had been on their trail for some months.

In a statement the deputy spokesman of the police, Brigadier General Sulistyo Ishak, said the terrorists belonged to the Kompak terror group which “has strong ties to other groups in Singapore like Jemaah Islamiyah, Jundullah and Negara Islam Indonesia, which are working together to set up an Islamic state in Indonesia.”

The police decision to sound the alarm in Bali is also connected to the pending execution of the men responsible for a 2002 attack.

Time and place for the execution of the three Islamist militants will be made public by Friday.

Meanwhile Indonesian police has deployed more forces in the Cilacap district and in Bali ahead of the event. The level of security has also been raised in Wijaya Pura harbour, which is crossed by ferries to Nusakambangan Prison where Amrozi, Imam Samudra and Ali Ghufron are detained.

Of concern to police is also the fact that Kuta, one of Bali Island’s most famous tourist resorts, is hosting the Asian Beach Games.

Similarly, law enforcement authorities are aware that repeatedly during their trial the three men condemned for the attack and their supporters had made threats.