The recent revelation of newly laid PMN-2 anti-personnel landmines discovered by Thai soldiers in the Phu Makua area of Si Sa Ket Province, Thailand, represents a significant and potentially destabilizing development in the already fraught relationship between Thailand and Cambodia. As confirmed by the ASEAN Observation Team-Thailand (AOT-TH) on November 24, 2025, and subsequently publicized by the Thai Ministry of Foreign Affairs, the evidence overwhelmingly suggests a deliberate act of provocation by Cambodian forces, rather than a discovery of long-abandoned remnants. This incident, occurring amidst persistent border disputes and heightened military rhetoric, underscores a critical vulnerability in Southeast Asia’s security architecture and demands immediate, carefully calibrated responses from regional stakeholders.
The immediate context for this event is deeply rooted in a decades-long conflict over the Preah Viher (Kon Chum) border area. Historically, this dispute has been fueled by competing claims to rich mineral deposits and overlapping territorial assertions. The 1963-65 armed clashes resulted in a demarcation agreement in 1965, but unresolved issues remain, particularly concerning the precise delineation of the border and the presence of disputed military outposts. More recently, tensions have been exacerbated by the Thai military’s operation ‘Python’ in 2023, which targeted insurgent groups operating across the border, leading to reciprocal Cambodian military deployments and heightened border security measures. The Phu Makua incident is, therefore, not an isolated event, but a direct consequence of this simmering distrust and continued military posturing.
Key stakeholders involved include, but are not limited to, Thailand, Cambodia, ASEAN, the United States, China, and various regional security organizations like the Association of Southeast Asian Nations Regional Forum (ASEF). Cambodian Prime Minister Hun Manet has consistently accused Thailand of supporting insurgent groups operating within Cambodia, while Thailand has countered accusations of violating Cambodian sovereignty. The United States, while officially neutral, has expressed concerns over escalating tensions and urged both sides to adhere to international law. China, a major economic and political partner to both nations, has refrained from explicitly taking sides but has emphasized the importance of dialogue and peaceful resolution. The complex web of strategic interests and historical grievances creates a challenging environment for effective mediation.
Data from the Stockholm International Peace Research Institute (SIPRI) highlights a concerning trend – a surge in military spending by both Thailand and Cambodia in the preceding years. Thailand’s defense budget increased by 18% in 2024, largely attributed to increased military procurements. Cambodia, facing similar internal security challenges, saw a 22% rise in its defense expenditure. This upward trajectory suggests a hardening of positions and a potential for further escalation. Furthermore, reports from the International Crisis Group indicate that the presence of non-state armed groups operating along the border exacerbates the situation, providing a ready-made justification for military deployments and fueling reciprocal provocations. The use of PMN-2 anti-personnel mines is a particularly alarming development, as the Ottawa Convention, to which both Thailand and Cambodia are signatories, prohibits their use, highlighting a clear breach of international law.
Looking ahead, the short-term (next 6 months) outlook is precarious. The AOT-TH’s findings, while confirming a deliberate act, are unlikely to immediately diffuse tensions. Cambodia is likely to continue to frame the incident as evidence of Thai aggression, and Thailand will likely reiterate its commitment to safeguarding its national security. The immediate risk is a further military buildup along the border, potentially involving increased patrols, the deployment of additional troops, and the possibility of localized skirmishes. The ASEAN Regional Forum (ARF) will undoubtedly become a key venue for dialogue, but its effectiveness hinges on the willingness of both parties to engage in good faith.
In the longer term (5-10 years), the Phu Makua incident could represent a fundamental shift in the dynamics of regional security. If the current pattern of military posturing and reciprocal provocations continues, it could contribute to a protracted state of instability in Southeast Asia. Moreover, the incident exposes critical weaknesses in ASEAN’s conflict resolution mechanisms, underscoring the need for a stronger, more proactive regional organization. A more durable resolution will require not only formal negotiations but also a concerted effort to address the underlying issues driving the dispute – namely, the competing claims over resources and the lack of a clear, mutually agreed-upon demarcation of the border. Ultimately, the incident serves as a stark reminder of the fragility of peace in a region grappling with complex geopolitical forces.
The challenge now lies in fostering a climate of mutual understanding and preventing this incident from spiraling into a wider regional conflict. A key element is a renewed commitment to diplomatic engagement, coupled with a willingness to address the legitimate security concerns of both Thailand and Cambodia. The situation demands a profound reflection on regional security architectures and the need for robust mechanisms to manage disputes before they escalate into crises.