by Cherdchai Chaivaivid

Signing of the joint declaration by Cambodia and Thailand, on the sidelines of the ASEAN summit and in the presence of the Malaysian Prime Minister and President Donald Trump, October 26.

Iwish to bring to your urgent attention and that of the members of the United Nations Security Council the recent developments with regard to Cambodia’s continued acts of hostilities and provocation against Thailand as follows:

1. On 26 October 2025, through the good offices of the Prime Minister of Malaysia, in his capacity as the Chair of the Association of Southeast Asian Nations (ASEAN), and the President of the United States of America, the Joint Declaration by the Prime Minister of Thailand and the Prime Minister of Cambodia on the outcomes of their meeting in Kuala Lumpur, Malaysia was signed by both parties, marking a significant progress and commitment towards the peaceful settlement of the Thailand-Cambodia border situation.

2. Thailand has since then taken all necessary steps to uphold the commitments made under the Joint Declaration and made progress on its implementation, in the spirit of good neighbourliness, ASEAN solidarity and full respect for international law, including the Charter of the United Nations.

3. Particularly on the implementation of humanitarian demining coordination, Thailand and Cambodia have established a Joint Coordinating Task Force on Humanitarian Demining, along with standard operating procedures, to determine priority border areas for humanitarian demining, as well as to coordinate the planning and implementation of humanitarian demining operations. Under this mechanism, both countries have already agreed on the first priority areas for humanitarian demining in Sa Kaeo Province in Thailand.

4. Regrettably, on 10 November 2025 at 09.30 hours – just two weeks after the signing of the Joint Declaration and amidst positive momentum on humanitarian demining cooperation – Thai soldiers from the 1161st Paramilitary Company, while conducting a patrol along a regular route in Huai Thamariya area, Si Saket Province in Thailand, stepped on a landmine, which again was identified as newly emplaced PMN-2 landmine. The explosion seriously injured four Thai soldiers, one of whom lost his right leg. It is important to stress that since 16 July 2025, seven landmine incidents within Thai territory, including the above-mentioned one, have caused permanent disabilities to seven soldiers, each losing a leg. Cambodia’s repeated use of landmines is premeditated and unlawful, constituting a flagrant violation of the Anti-Personnel Mine Ban Convention , the Charter of the United Nations, including Article 2 (4), and Thailand’s sovereignty and territorial integrity.

5. Following this recent landmine incident, Thailand promptly submitted an official note to the Ambassador and Permanent Representative of Japan to the Conference on Disarmament as the President-designate of the twenty-second Meeting of the State Parties to the Anti-Personnel Mine Ban Convention, reporting the incident and raising concerns over Cambodia’s continued violation of the Convention. A copy of the note is attached herewith (see annex).

6. Furthermore, it is deeply regrettable that, on 12 November 2025 at 16.10 hours, Cambodian soldiers deliberately opened fire on Thai troops stationed in the area of Ban Nong Ya Kaew, Khok Sung District, Sa Kaeo Province – well within Thai territory – in clear violation of Thailand’s sovereignty and territorial integrity. The Thai troops were compelled to return warning shots from small arms in self-defence, strictly in accordance with the principles of necessity and proportionality. The exchange of fire lasted until 16.15 hours, during which a total of 30 shots were fired from the Cambodian side, causing damages to the Thai side. Furthermore, at 17.55 hours, about five rounds of gunfire from a machine gun were heard from the Cambodian side, but the Thai side did not return fire. Our response to this round of provocations by Cambodia was an exercise of the inherent right of self-defense fully in consistent with international law and the Charter of the United Nations.

7. It is also deplorable that, following the incident, Cambodian officials and media outlets disseminated false information alleging that the incident was initiated by the Thai side. This clearly demonstrates that the incident was yet another premeditated provocation by Cambodia, seemingly intended to deflect attention from its responsibility for the recent landmine incident. Thailand categorically rejects Cambodia’s continued groundless accusations clearly aimed at distorting the facts and deliberately undermining Thailand’s credibility within the international community.

8. Cambodia’s continued hostilities and provocation towards Thailand only serve to escalate tensions and demonstrate its clear breach of the shared commitment under the Joint Declaration, derailing the efforts by all sides to promote a peaceful resolution to the ongoing situation and eroding mutual trust and confidence. Thailand therefore is compelled to pause the implementation of the Joint Declaration, as deemed appropriate, until it can be assured of Cambodia’s sincerity and good faith.

9. Despite Cambodia’s deliberate and persistent acts of aggression and hostilities, Thailand will continue to exercise utmost restraint in defending its sovereignty and territorial integrity and remain firmly committed to the peaceful settlement of disputes. Moreover, Thailand will proceed with two critical elements of the Joint Declaration: humanitarian demining, which is essential to safeguard innocent citizens, and combating transnational scamming networks that affect not only our citizens but millions of people worldwide.

10. In this regard, Thailand calls upon the international community to urge Cambodia to take full responsibility and cease all acts of hostilities and provocations that inflict harm upon the Thai people and constitute a blatant violation of Thailand’s sovereignty and territorial integrity. Cambodia must fully honour and immediately act in accordance with its obligations under international law and the Charter of the United Nations and demonstrate its good faith and sincerity in finding a path for peace with Thailand.

In this connection, I have the honour to request that the present letter and its annex be circulated to all members of the Council for their urgent attention.

Cherdchai Chaivaivid