Three Asean countries - Indonesia, Malaysia and the Philippines - agreed this month on joint maritime patrols to ward off potential terrorist threats. The move was sparked by the kidnapping of 14 Indonesian and four Malaysian seamen by thugs with connections to the Philippines-based Abu Sayyaf terrorist group, as well as by its beheading of a Canadian citizen.
The trilateral initiative is also an important step towards restricting international crime, and ridding the waters in the region of pirates, some of whom are thought to have ties with Abu Sayyaf.
Asean members Malaysia, the Philippines, Indonesia and Singapore are all considered primary targets because of extremist groups such as Al-Qaeda, Abu Sayyaf, the Moro Islamic Liberation Front and Jemaah Islamiyah that have been operating within the region for years.
According to a recent report published by Mr Patrick Skinner of the New York-based security consulting firm The Soufan Group, "the Islamic State in Iraq and Syria (ISIS) has yet to establish a South-east Asian wiliyah (state), but it is likely that it will do so this year, as its grip on Syria and Iraq weakens".
What are the implications of the joint patrol move by Malaysia, Indonesia and the Philippines, and what does it signal for Asean inter-member cooperation?
With Asean members intensifying their military cooperation and improving their respective military capabilities, China may feel suspicious of their intentions regarding its maritime claims. China is clearly nervous about recent developments in that regard, as shown by a recent proposal for a new joint statement with Asean calling for restraint of all parties with maritime claims.
Malaysia has long emphasised the need for international cooperation if global terrorism is to be reined in. Significantly, in September last year, Kuala Lumpur became the second Asean country after Singapore to join the US-led anti-ISIS global coalition and has plans to set up a regional centre to counter ISIS propaganda.
However, while cooperating within the anti-terror alliance is mostly unproblematic, conducting counter-terrorist naval patrols with other Asean members is trickier.
First, Malaysia is locked in bilateral territorial disputes with Indonesia and the Philippines, making patrols in adjacent areas problematic. The Philippines lays claim to part of Malaysian Borneo, and after a southern Philippines-based incursion in 2013, Malaysia could now be tempted to utilise the new joint patrols to preclude other such incursions.
Indonesia, on the other hand, has used the territorial conflict over the Ambalat region as a means to ramp up its military modernisation.
Second, South-east Asian states have been building up their military power in reaction to assertiveness by China. With Asean members intensifying their military cooperation and improving their respective military capabilities, China may feel suspicious of their intentions regarding its maritime claims.
China is clearly nervous about recent developments in that regard, as shown by a recent proposal for a new joint statement with Asean calling for restraint of all parties with maritime claims.
Third, it is unclear to what extent the joint patrol plans will come into conflict with Asean's neutrality and its principle of non-intervention.
The three countries are also wary of a possible loss of sovereignty resulting from these patrols, as expressed by Indonesian Foreign Minister Retno Marsudi. She stated that any cooperation "must be agreed on without any of them sacrificing their sovereignty", adding that "negotiations will go on until we find a common understanding and are able to conduct joint operations".
Furthermore, Mr Agus R. Barnas, a spokesman for Indonesia's Coordinating Ministry for Politics, Law and Security, stressed that each country "will patrol in their own territories in the border areas of the three nations, but the patrol will be integrated".
The bottom line: As long as Asean states set aside petty divisions and competing territorial claims, the joint maritime patrols could be a quantum leap in the collective fight against ISIS, and aid in making up for Asean's shortfalls in the realm of maritime security and safety.
Asean has shown weakness in the Abu Sayyaf abductions, because the organisation has no coordinated regional security policies, forcing individual members to deal with particular threats entirely by themselves. In the long run, improved coordination among all Asean members in the fight against extremism could raise Asean's credibility and effectiveness as a leader in counter-terrorism.
The likelihood of Malaysia turning into a major ISIS stronghold in the near future, meanwhile, remains the subject of much debate, but there is no doubt the Malaysian government is taking the threat very seriously.
Law enforcement authorities have been proactive in efforts to prevent attacks. In March this year, 15 people believed to have been planning large-scale attacks in the country on orders of a Malaysian ISIS recruiter were apprehended, bringing the number of suspected militants arrested to 157 since 2013.
Counter-terrorism experts say that law enforcement officers have also kept a close eye on flight manifests, and stepped up border controls to prevent the return of battle-hardened fighters to Malaysia, and new recruits from reaching Iraq and Syria.
Experience in counter-terrorism operations has led to the establishment of various anti-terrorist units within the armed forces and the police, which may explain why Malaysia has so far been spared extremist assaults of the sort Indonesia has suffered.
Some of these policies have come under fire from human rights activists for being passed too quickly and for being too heavy-handed. However, Malaysia appears to be on its way to establishing itself as a major force in the fight against terrorism.
The joint maritime patrols are a welcome step forward that shows that Asean nations are able to put behind their political differences and fight against a common enemy. Kuala Lumpur's approach to the issue - reaching out to other affected states, and joining the US-led alliance - indicates an increasingly organised resistance to ISIS.
• The writer is an independent researcher on Asian military and international affairs based in Taiwan.