
A spate of suicide bomb attacks on three churches and the police headquarters in the Indonesian city of Surabaya last month shocked the country and made headlines around the world. The attacks came less than a week after more than 150 Islamist militant convicts laid siege to a prison on the outskirts of Jakarta, killing five police officers and exposing the growing threat posed to Indonesia by ISIS and its affiliates. This report provides an overview of the major terrorist incidents that shook the country last month and discusses the response of both Indonesia’s lawmakers and law enforcement agencies.
After avoiding a major Islamist attack for more than two years – since the ISIS-claimed gun and bomb attack on Jakarta’s Thamrin business district killed four civilians in January 2016 – signs of increased militant activity first rose to the surface on 8 May, when armed clashes broke-out between convicted terrorists and police officers at a high-security prison in Depok, near the Indonesian capital Jakarta. The situation quickly escalated into a tense two-day siege, resulting in the death of five police officers and one militant. The siege eventually came to an end after officers from the elite police counter-terrorism unit – Detachment 88 – stormed the prison in an attempt to free hostages, triggering the militants’ surrender. Soon after the incident, President Joko Widodo said the state would ‘never give space to terrorism or any effort to undermine national security’. However, worse was still to come.
On 13 May, suicide bombers linked to the Jamaah Ansharut Daulah (JAD) militant group detonated their devices at three Christian churches in the East Java city of Surabaya, killing at least 13 people and leaving in excess of 30 wounded. ISIS soon claimed responsibility for the attack, and authorities later revealed that all six of the attackers came from the same family, several of whom were young children. The following morning, another five suicide bombers blew themselves up nearby at the city’s police headquarters, leaving ten people wounded. As with the first incident, the attack was again carried-out by a single family. On 16 May, a third attack occurred in the space of just three days when four men wielding samurai swords attacked a police station in the city of Pekanbaru, in Riau province. A police officer was killed and three others injured, while all four of the attackers were shot dead at the scene.
The wave of attacks shocked Indonesia and its neighbours, despite Southeast Asian countries having already been on a raised state of alert since last year’s siege of Marawi in the Philippines and amid fears of ISIS fighters returning from war zones in the Middle East. However, the unexpectedly large scale and nature of the attacks – in the sense that children were used – heightened the shock factor.
In the wake of the turbulent few days endured in mid-May, Indonesia’s authorities have been swift to respond. In a direct response to the siege at the prison in Depok, police announced that all of the 155 militants involved would be transferred to a maximum-security detention facility on Nusakambangan island in Central Java. In the weeks immediately following the attacks in Surabaya and Pekanbaru, officers from the Detachment 88 counter-terrorism squad launched a series of raids across the nation. On 22 May, national police chief Tito Karnavian announced that 74 suspects had been arrested in the previous ten days, adding that officers had seized ‘ready-made bombs and other explosive materials’.

In some instances, militants tried to resist arrest, resulting in several armed skirmishes and fatalities. On 10 May two jihadists attempting to join the prison siege in Depok were shot by police officers after attempting to seize their weapons in Bekasi, leaving one dead while the other sustained injuries and was later taken into custody. On 14 May two suspects were killed by police in Sidoarjo after opening fire on officers. Two days later a militant was shot dead in Tanjung Balai in similar circumstances. Of the 74 people arrested, Karnavian said most had ties to JAD while at least 37 of the suspects were linked to the Surabaya bombings. Describing the police response, Karnavian said on 31 May that his force had ‘moved fast’ to ‘identify the perpetrators’ and restore a semblance of stability in the country.
President Widodo condemned the attacks as ‘barbaric’, labelling the actions of the perpetrators as ‘cowardly’. Widodo also urged lawmakers to push through a raft of new counter-terrorism legislation which was first proposed after the Thamrin attack in early-2016 but has since faced repeated hurdles in Parliament. The national police chief also echoed the need for tougher anti-terror measures, with Karnavian requesting assistance from the army to conduct joint operations targeting JAD and several other domestic ISIS-inspired militant groups, such as Jamaah Ansharut Tauhid (JAT) and Mujahidin Indonesia Timur (MIT). Less than a week after the attacks, President Widodo confirmed that he would reactivate the military’s Joint Special Operations Command – known as Koopsusgab – to aid the police in counter-terrorism operations. A greater role for Indonesia’s armed forces in tackling terrorism now appears certain as public opinion has shifted in the wake of the sudden resurgence in jihadist violence.
In the final days of May, lawmakers in Jakarta passed the new counter-terrorism laws first proposed more than two years ago. The new legislation is set to give the authorities enhanced and wide-ranging powers to arrest and question suspected terrorists at an earlier stage in investigations. Police will now be permitted to detain terror suspects for up to 21 days, increased from the previous limit of seven. Officers will also be able to apply for an extension if more time is required. Prosecuting authorities will now also be able to charge individuals suspected of either supporting or recruiting for both foreign and domestic militant groups. Sentences are also set to be increased for those convicted, including lengthy jail terms and the death penalty for those found guilty of the most serious terrorism offences.
The attacks by Islamist militants in Surabaya and Pekanbaru expose the growing threat posed to the country by ISIS and its regional affiliates: JAD, JAT, MIT and the remnants of Jemaah Islamiyah (JI). A secondary threat also emanates from so-called ‘lone wolves’, who may strike at any moment using unsophisticated weapons such as knives or vehicles. These low-tech attacks require little planning and are notoriously difficult for the intelligence services to prevent. At present, Indonesia is facing a dual threat from both homegrown jihadists and foreign fighters returning from conflict zones in ISIS’ former heartlands in Syria and Iraq. Just a few weeks ago, President Widodo’s Chief-of-Staff revealed that almost 1,500 Indonesian citizens have attempted to travel to the Middle East to fight alongside ISIS and other extremist groups in recent years – and many of them succeeded in their aim. Of these, 590 are thought to remain in Syria while 103 have been killed and 86 have already returned of their own accord. In addition, more than 500 were forcibly deported back to Indonesia while 171 others have been prevented from leaving the country after suspicions that they intended to take up arms overseas.
These figures may represent just the tip of the iceberg in terms of the threat posed by Islamist militants in Indonesia, a country which has until recently done a remarkable job in keeping the jihadists at bay. In the current climate however, the task for intelligence and law enforcement agencies has become far more difficult. Despite the wave of arrests and introduction of new counter-terrorism laws since the attacks last month, it may be many years before Indonesia can turn the tide on its rising militancy.