Background
Boundary demarcation between Cambodia and Thailand is administered through bilateral mechanisms, notably the Joint Boundary Commission (JBC) and its Joint Survey Teams (JSTs), which are assigned to carry out on-the-ground surveys and clarify the international boundary line. The JBC framework is supported by bilateral instruments including the 2000 memorandum of understanding (MOU) and the 2003 terms of reference (TOR) for joint survey and demarcation activities.
On 17 May 2026 at 09:00, the Cambodian Liaison Group (CLG) coordinated with the ASEAN Observer Team (AOT), led by the Philippines as Head of Mission, to observe, verify, and report on the border situation at Seila Khmer Village in O Bei Chon Commune, O Chrov District, Banteay Meanchey Province. The Cambodian government publicly reaffirmed that it does not recognise any change to the Cambodia–Thailand international boundary that departs from the Franco–Siamese conventions, Indo‑China–Siam demarcation maps, agreed JBC minutes, the 2000 MOU, or the 2003 TOR, and it rejects boundary alteration resulting from the use of force.
Key Developments
The CLG–AOT observation took place at a site described by Cambodian authorities as long cultivated and continuously under Cambodian occupation since the emergency ceasefire came into effect on 27 December 2025. The mission included verification of local conditions and an assessment of compliance with the stabilisation measures set out in the Joint Declaration accompanying the ceasefire. The Ministry of National Defence issued a formal press statement to inform national and international media about the mission and Phnom Penh’s position on demarcation authority.
Institutional Role
The Cambodian Liaison Group functions as the domestic coordinating entity for the operation, while the ASEAN Observer Team serves as an external monitoring and reporting mechanism under ASEAN’s observer role in the Cambodia–Thailand border stabilisation process. Cambodian authorities emphasised that armed forces and local officials do not have mandate to define or mark the boundary line on the ground, and that such tasks fall to JSTs operating under the JBC structure.
Operational Implications
The Ministry of National Defence urged the Thai side to dispatch Joint Survey Teams to the terrain and to reconvene the Joint Boundary Commission at the earliest opportunity to resume delimitation work. Phnom Penh also reaffirmed its commitment to implement the Joint Statement of the Third Special Meeting of the Cambodia–Thailand General Border Committee (27 December 2025) and the Joint Declaration on the Peace Agreement (26 October 2025) as part of efforts to restore normalcy and long-term stability in the border area.
Official source: Ministry of National Defence press release, 17 May 2026. Original source: https://www.facebook.com/Ministrydefence/posts/pfbid02FR7hnz8N9Sq3s66herNETzSK3up642LmUwFcHBhsbXsLDRSEVgxYxMx3tSALB7FZl
