Indonesian police have arrested four people who were allegedly planning to set off a bomb outside the presidential palace in Jakarta.
They are also suspected to have links to a terrorist network run from Syria, local media reports said.
The arrests took place on Saturday, after the anti-terrorism cell Densus 88 raided a house in the locality of Bekasi, in eastern Jakarta, from where they recovered a package with three kilos of explosives ready to be detonated.
Police suspect the detainees wanted to set off the bomb on Sunday during the change of guard ceremony that takes place at the entry gates to the presidential palace complex, a site where tourists usually gather to watch the event.
Had it been detonated, the bomb could have destroyed everything within a 300-meter radius, Jakarta police spokesman Senior Commander Raden Prabowo Argo Yuwono said at a press conference held on Saturday night, according to the daily The Jakarta Post.
The spokesman said the bomb was meant to be detonated by a woman, who was followed by the police to a post office, and later to a house in Bekasi, before being arrested along with two male accomplices.
A fourth person was detained later from the city of Solo, in central Java.
The bomb contained the same explosive material that was used in the 2005 London attacks and found in the suicide jackets of the 2015 Paris attackers, local press reported.
Police spokesman Awi Setiyono said the plan was the brainchild of Bahrun Naim, believed by authorities to be in Syria.
Bahrun Naim is one of the leaders of the Katibah Nusantara - a brigade of terrorist group Islamic State in the Middle East - made up of Malay-speaking militants from Malaysia, Indonesia and the Philippines.
Authorities blame him for instigating attacks in Indonesia and for being behind several attack bids foiled by law enforcement during the past year.
One of these was the armed attack on a central Jakarta cafeteria in January this year, in which all four attackers died, as well as four civilians, following a shootout with police.
Indonesia, 88 per cent of whose 260-million population is Muslim, has suffered several Islamist attacks, including one that occurred on the resort island of Bali in 2002 and left 202 dead, mostly foreign tourists.
