On the website www.smartraveller.gov.au (run by Australia's Department of Foreign Affairs and Trade), Australia's government states that places of worship in Indonesia as well as crowded places frequently visited by foreigners (such as nightclubs, bars, international hotels, restaurants and airports) are particularly vulnerable to a possible terrorist attack.

However, a spokesman of the Indonesian Police - responding to the latest warning issued by Australian authorities - said there were no indications of an immediate attack. The government of Indonesia did increase security measures - including the cracking down on suspected militants - since the January attack in Jakarta.

Journeys to Central Sulawesi (specifically the Poso district) are discouraged by Australian authorities as this province has been the center of the Tinombala operation, an operation that aims to capture Indonesia's most-wanted terrorist Abu "Santoso" Wardah, who is believed to lead the East Indonesia Mujahidin terrorist cells. This group is known for its attacks on Indonesian security forces.

Journeys to Papua are discouraged as there have been a series of violent attacks in the area around the Freeport Mine since July 2009.

Earlier this week the United States warned about possible Islamic State-linked terrorist attacks in Southeast Asia, while Australia issued a warning about attacks in (and around) Kuala Lumpur, the capital city of Malaysia. Since the attack in Jakarta in January, Malaysia has been on high alert, particularly after a series of alleged terrorist plots were uncovered. Islamic State claimed responsibility for the recent Jakarta attacks.

The viciously militant Islamic State, known for its brutal mass killings, abductions, beheadings, and crucifixions, has been in the news headlines since 2014 when it gained control over large pieces of territory in Syria and Iraq, declaring the establishment of a caliphate ruled under Islamic Law (sharia). The organization has attracted support from radical Muslims across the globe, including Indonesia. Although being a minority among the estimated 200 million Muslim inhabitants of Indonesia, there exists a radical Muslim community in the country that not only believes Islam should be the sole guidance in life but is also willing to use extreme measures to reform and uproot established conditions.

After having been plagued by terrorist attacks directed at symbols of the western world in Indonesia (the 2002/2005 Bali bombings and the 2003/2009 JW Marriott and Ritz Carlton hotel bombings), Indonesia's terrorist cells - now operating in smaller networks than before (as this makes it more difficult to trace them) - have been aiming at symbols of the Indonesian state since 2010 (for example police offers). This is most likely the reaction of local Islamic radicals to successful strategies of Indonesian authorities to combat terrorist cells. In 2003 a special counter-terrorism squad, Densus 88, was established which has had considerable success in weakening the Jema'ah Islamiyah network, a Southeast Asian militant group dedicated to the establishment of a caliphate in Southeast Asia.