On march 4, 2010, naval authorities issued a threat advisory of a potential terrorist plot targeting shipping interests transiting the Malacca Strait. Malaysia’s navy chief, Admiral Abdul Aziz Jaafar, warned that “terrorists are targeting specific tankers in the Malacca Strait and Singapore Strait.”[1] Singapore’s home affairs minister, Wong Kan Seng, said, “We received intelligence from our liaison partners about this possible plot to go and attack vessels coming through Singapore waters through the Strait of Malacca.”[2] The warning came on the heels of the arrests of 14 suspected terrorists at an alleged Jemaah Islamiya (JI) training camp on Indonesia’s Sumatra Island, which forms the eastern boundary of the waterway. [3]The incident has heightened regional and international concerns that the Malacca Strait could become a focus of Islamist maritime terrorism.[4]

In light of these recent threats, this article examines the likelihood of sea-based extremist violence in the region, JI’s capacity to operate in an offshore environment, and whether Southeast Asia is a place that al-Qa`ida would seek to exploit in terms of maritime attacks. It finds that the risk of a decisive maritime strike in the Malacca Strait is low, especially in the context of disrupting shipping interests as part of an economic war against the West.

Maritime Terrorism: The Jihadist Call to Arms

In May 2009, al-Qa`ida issued a global communiqué exhorting jihadists around the world to attack strategic maritime chokepoints as part of a wider economic war against the West.[5] On the surface, this call to arms seems to have direct relevance to the Malacca Strait. This particular maritime passage is one of the most important and busiest in the world, seeing an average of 50,000 transits a year that account for around a third of the world’s trade and oil shipments as well as much of its liquefied natural gas (LNG).[6] The Malacca Strait is also highly prone to congestion and bottlenecks, measuring just over 1.5 miles wide at the narrowest point.[7]

While there is little doubt concerning the economic salience of the Malacca Strait, carrying out decisive attacks against ships transiting through this corridor is somewhat more challenging than commonly portrayed. One of the most frequently postulated scenarios is that terrorists could attempt to disrupt the commercial viability of the Strait, either by detonating a hijacked oil or LNG tanker to shut down a prominent commercial terminal (such as the Port of Singapore) or by scuttling a large ship to block the through-passage of maritime traffic.[8] Although theoretically possible, realization of both attack contingencies would be difficult to achieve.

Igniting pressurized LNG or oil is technically problematic. Unless these substances vent in their liquid form and mix with air in the correct ratio, the probability of either substance fully catching fire is extremely low. Even if this did occur, the lateral force of any subsequent explosion would likely be contained by the tanker’s hull, which would force the destructive energy upwards rather than outwards (thus minimizing its destructive potential).[9] Sinking a major oceangoing freighter is equally as challenging and would, at a minimum, require the perpetrating group to have ready access to a large quantity of explosives, the time and means to transport this material and the expertise to know where to place the bombs to cause a critical breach. These logistical and knowledge barriers would pose formidable barriers for a single attack—much less an assault that targeted two or three ships (which would be required to truly block the Strait).[10]

An external ramming strike using a fast inshore attack craft (FIAC) arguably represents a more realistic scenario and is certainly one that has been used in the past. Leveraging these vessels as an attack platform offers the advantages of money, deftness and surprise in that FIACs are cheap, easy to handle and anonymous enough to mingle with other maritime traffic.[11] Even an FIAC-mounted attack, however, has a questionable prospect of causing a critical breach. Indeed, as the suicide bombings against the USS Cole in 2000 and the MV Limburg in 2002 highlighted, if the site of the impact does not accord with weak points in the ship’s skeletal design, it is unlikely that catastrophic damage would result.[12]

By far the most vulnerable vessel to terrorist aggression is a passenger ferry since its very purpose—to move large numbers of people as quickly and efficiently as possible—necessarily precludes the option for concerted (and some might argue even basic) security. Moreover, these ships generally sail at or above full capacity and are often characterized by certain design features (notably light flammable “outer-skins,” thin hulls and open car decks that lack stabilizing bulkheads) that make them highly susceptible to flooding and sinking.[13] Nevertheless, ferries only constitute a small percentage of the maritime traffic that transits the Malacca Strait, they are generally not sizeable vessels (meaning that sinking them would be unlikely to cause a major blockage along the Strait) and their value as a strategic economic target, at least in this particular vicinity, is limited.[14]

JI and Maritime Attacks

Al-Qa`ida’s May 2009 communiqué also had relevance to JI on account of the group’s past links to the al-Qa`ida transnational network. These ties, however, have mostly atrophied during the last five years, and while JI was certainly prepared to accept Usama bin Ladin’s past financial and operational support, the group always tended to prioritize its own local objectives over that of its erstwhile backer. Since the mid-2000s, this agenda has essentially centered on reconsolidating and building strength in Indonesia by returning the movement to its historical Darul Islam roots.[15] Executing attacks in the Malacca Strait at the behest of an organization based on the other side of the world would have little, if any, relevance to this strategic priority.

Just as importantly, JI has no maritime tradition, and apart from unsubstantiated allegations has never sought to extend its operational realm beyond a territorial environment. The group is not known to have any mariner human or technical skill sets at its disposal, and given its current weakened and disaggregated state would be unlikely to invest the limited resources it has in trying to develop an entirely new (and in many respects unproven) attack profile.[16]

Moreover, JI’s center of gravity lies in Indonesia’s Java, which is by no means contiguous to the Malacca Strait. Although commentators have claimed that the militants recently arrested in Indonesia’s northern Sumatra were attending a JI training camp, no evidence has yet to surface that this was the case or, indeed, that those detained were Islamist terrorists seeking to target ships transiting the seaway.[17] The fact that Achenese Muslims, including former insurgents associated with Gerakan Aceh Merdeka, have historically (and strongly) shunned attempts by JI to gain a foothold in the region also clouds the veracity of these claims.[18]

The Malacca Strait an Unlikely Target

The Malacca Strait constitutes an important maritime corridor that presumably accords well with al-Qa`ida’s purported aim to disrupt Western shipping interests. For two basic, inter-related reasons, however, the group would probably seek to realize this objective elsewhere. First, the Malacca Strait is well guarded. Indonesia, Malaysia and Singapore are all fully committed to ensuring the safety of the waterway through the exchange of intelligence and the regular conduct of joint patrols and exercises.[19] Since 2005, a limited but growing regime of wider airborne surveillance has also been in place. Known as the “Eye in the Sky,” the initiative includes the three littoral states in addition to Thailand and the Philippines.[20] Under the scheme, each participating country has made available two planes and commits to flying two sorties a week over the Strait—meaning that for every seven days there are at least 16 hours of continual coverage over the waterway.[21]

Second, there are other strategic chokepoints that offer a more conducive operational theater. Notable in this regard is the Gulf of Aden. Not only does this passage serve as a vital and largely non-substitutable[22] trade and energy link between the Indian Ocean and Europe, it also abuts Somalia—a state that has not seen a functioning system of governance since 1991. Moreover, there are at least two groups in this region that are well placed to hit maritime targets, both of which have stated their full allegiance to the Islamist enterprise: al-Shabab, which in 2010 for the first time announced its solidarity with Bin Ladin and readiness to stage attacks off the Horn of Africa in pursuit of his ideological and militant agenda;[23] and al-Qa`ida in the Arabian Peninsula (AQAP), which in 2009 declared a “mast media” campaign urging Muslims to gather all relevant information on American vessels sailing near Yemen, including data on payloads, crews and how they are serviced by other states.[24]


Although the Malacca Strait represents a key maritime corridor and has been the focus of a number of postulated risk scenarios, the threat of a major terrorist strike appears low. The waterway is well guarded and there is currently no group in the immediate region with the necessary skills or motivation to conduct decisive operations against maritime assets. The most likely entity to attempt an attack would be al-Qa`ida, with the principal objective being to realize the movement’s self-defined economic jihad against the West. Nevertheless, there is no evidence that the organization is presently working with affiliates in Southeast Asia to further this goal. Moreover, there are other theaters that offer a far more conducive environment for targeting sea-based commercial and energy assets that have critical relevance to the functioning of the contemporary global order.

Dr. Peter Chalk is a Senior Policy Analyst with the RAND Corporation, Santa Monica, California. He specializes in transnational security threats and has worked on a range of projects in South and Southeast Asia, sub-Saharan Africa and Latin America. He is also Associate Editor of Studies in Conflict and Terrorism, one of the foremost journals in the international security field, and serves as an Adjunct Professor with the Naval Postgraduate School in Monterey, California and the Asia Pacific Center for Security Studies (APCSS) in Honolulu, Hawaii.

[1] Alex Kennedy, “Tankers Warned of Terror Threat in Malacca Strait,” Associated Press, March 4, 2010.

[2] “Singapore Raises Security Alert Levels After Malacca Strait Threat,” Reuters, March 5, 2010.

[3] Ibid.; “14 Suspects Charged Under Indonesia’s Anti-Terror Laws,” ChannelNewsAsia.com, March 4, 2010.

[4]  The Joint War Council of the Lloyds Market Association designated the Malacca Strait an area of Perceived Enhanced Risk in July 2005. For details, see Peter Chalk, The Maritime Dimension of International Security (Santa Monica, CA: RAND, 2008), p. 33; Martin Murphy, Small Boats, Weak States, Dirty Money (New York: Columbia University Press, 2009), pp. 83-84; Graham Gerard Ong-Webb, “Introduction: Southeast Asian Piracy: Research and Developments,” in Graham Gerard Ong-Webb ed., Piracy, Maritime Terrorism and Securing the Malacca Straits (Singapore: ISEAS, 2006), p. xxxiv.

[5]  “Maritime Terrorism in the Eyes of Al-Qaeda,” International Institute for Counter-Terrorism, November 2009. The communiqué was posted in Jihad Press, an electronic newspaper.

[6] “Country Analysis Briefs: World Oil Transit Chokepoints,” U.S. Energy Information Administration, January 2008; “Singapore Warns of Threat to Tankers in Malacca Strait,” BBC, March 4, 2010.

[7] Ibid.; Michael Richardson, A Time Bomb for Global Trade: Maritime-Related Terrorism in an Age of Weapons of Mass Destruction (Singapore: ISEAS, 2004), p. 38; “Ships Collide Off Malaysia Coast,” al-Jazira, August 19, 2009.

[8]  See, for instance, Richardson, pp. 38-45; Mansoor Ijaz, “The Maritime Threat from al-Qaeda,” Financial Times, October 19, 2003; Jerry Frank, “Big Business Gets Political Over Rising Global Risks,” Lloyds List, January 24, 2008; Murphy, Small Boats, Weak States, Dirty Money, p. 266; “Security Raised in Malacca Strait After Terror Warning.”

[9]  Martin Murphy, “Maritime Terrorism: The Threat in Context,” Jane’s Intelligence Review, February 2006, p. 21; “Facts About LNG,” Sound Energy Solutions, available online at www.soundenergysolutions.com.

[10]  Chalk, The Maritime Dimension of International Security, pp. 12, 23; Dennis Blair and Kenneth Lieberthal, “Smooth Sailing: The World’s Shipping Lanes Are Safe,” Foreign Affairs 86:3 (2007). It should also be noted that the Malacca Strait is not a truly non-substitutable waterway. Blocking the passageway would require, at most, only an extra two to three days steaming time which would not unduly impact the overall cost and transport of global freight.

[11]  Murphy, “Maritime Terrorism: The Threat in Context,” p. 23.

[12]  Rupert Herbert-Burns, “Terrorism in the Early 21st Century Maritime Domain,” in Joshua Ho and Catherine Zara Raymond eds., The Best of Times, the Worst of Times: Maritime Security in the Asia-Pacific (Singapore: World Scientific, 2005), pp. 164-165.

[13]  For more on the vulnerability of ferries to terrorist attacks, see Chalk, The Maritime Dimension of International Security, p. XX; Michael Greenberg, Peter Chalk, Henry Willis, Ivan Khilko and David Ortiz, Maritime Terrorism. Risk and Liability (Santa Monica, CA: RAND, 2006).

[14]  Of course, this does not preclude the possibility of attacks against ferries in other parts of Southeast Asia where they are far more common and critical to the day-to-day lives of many ordinary citizens. The Philippines, for instance, has seen several attacks on these vessels, including the 2004 bombing of SuperFerry 14, which left 116 people dead.

[15]  Peter Chalk, Angel Rabasa, William Rosenau and Leanne Piggott, The Evolving Terrorist Threat to Southeast Asia: A Net Assessment (Santa Monica, CA: RAND, 2009), p. 102. The basic aim of Darul Islam was to overthrow the secular Indonesian state that emerged in the wake of independence from the Netherlands and replace it with one based on the full observance of Shari`a law.

[16]  See, for instance, Stefan Eklof Amirell, “Political Piracy and Maritime Terrorism,” in Graham Gerard Ong-Webb, Piracy, Maritime Terrorism and Securing the Malacca Straits (Singapore: ISEAS, 2006), pp. 58-59.

[17]  Personal interviews, maritime security analysts, Copenhagen, Denmark, March 2010. Thus far, no evidence has surfaced that those arrested in northern Sumatra were connected to either JI’s mainstream or its so-called “pro-bombing bloc.” As noted in the text, JI has consistently failed to gain a footprint in this particular region. Moreover, most of the materiel seized in the purported camp—rifles, military uniforms, propaganda leaflets and videos of the 2002 Bali suicide bombings—strongly suggest preparations for a land-based attack as opposed to one aimed against maritime conveyance.

[18]  See, for instance, Leonard Sebastian, “The Indonesian Dilemma: How to Participate in the War on Terror Without Becoming a National Security State,” in Kumar Ramakrishna ed., After Bali: The Threat of Terrorism in Southeast Asia (Singapore: World Scientific, 2004).

[19]  The effectiveness of these measures has been reflected in the dramatic drop of piracy incidents reported in the Malacca Strait. According to statistics from the International Maritime Bureau (IMB), attacks have declined by roughly 83% during the past four years. See “Armed Robbery and Piracy Against Ships: Annual Report, 2009,” International Maritime Bureau, 2010, p. 5.

[20]  The three littoral states are Malaysia, Indonesia and Singapore.

[21]  Personal interview, maritime security specialists attending the “Comprehensive Responses to Terrorism Conference,” Cambodia, August 2009. Also see Ong-Webb, “Introduction,” pp. xxix-xxxi; Mohd Nasir Yusoff, “Eye-in-the-Sky-Initiative Over Malacca Straits from September 13,” Bernama, September 8, 2005.

[22]  In this respect, the Gulf of Aden offers a more attractive operational theater for carrying out terrorist attacks designed to disrupt the mechanics of global trade. If ships were precluded from transiting the waterway, they would be forced to re-route around the Cape of Good Hope in South Africa. This would add at least three weeks to an average journey, resulting in increased shipping costs of between $1.5 and $2 million to cover extra fuel, labor and time.

[23]  Huma Yusuf, “Somali Militant Group Al Shabab Aligns with Al-Qaeda,” Christian Science Monitor, February 10, 2010.

[24]  “Q&A: Yemen’s al-Qaeda Wing Gains Global Notoriety,” Reuters, January 13, 2010; Bill Gertz, “Navy Warns Ships About Al Qaeda Risk Near Yemen,” Washington Times, March 23, 2010.

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