Cambodia has urged Thailand to end its military incursions and unilateral activities in Cambodian territory, resume Cambodia-Thailand Joint Boundary Commission (JBC) work and fully implement the December 2025 ceasefire commitments, according to a letter submitted to the United Nations.
In a letter dated September 29, 2026, Ambassador Keo Chhea, Permanent Representative to the United Nations, responded to a statement delivered by Thailand’s Ambassador and Permanent Representative to the UN in New York, Cherdchai Chaivaivid, during the General Assembly’s general debate on September 28.
Cambodia expressed regret over what it described as Thailand’s attempt to distort the historical record and omit key facts about the border conflict, insisting that the dispute must be addressed through international law, peaceful negotiations and the implementation of existing agreements.
“The record is clear,” Keo Chhea wrote, stating that Thai armed forces launched military operations against Cambodian positions along the border on July 24, 2025, before expanding the offensive on December 7, 2025, involving tanks, heavy artillery, F-16 and Saab JAS Gripen fighter jets, drones and cluster munitions across several Cambodian provinces.
The letter said Cambodia had consistently documented the attacks and lodged protests through appropriate diplomatic channels.
Following the ceasefire established under the joint statement of December 27, 2025, Cambodia said it had continued documenting what it described as Thai military incursions, including the construction of fortifications, the laying of barbed wire, the installation of shipping containers and the unilateral movement of frontier positions into Cambodian sovereign territory.
Cambodia argued that such activities were inconsistent with commitments made by both sides to de-escalate tensions, rebuild confidence and refrain from actions that could worsen the situation.
“Confidence is strengthened not by declarations of intent alone but by consistent implementation of agreed commitments,” the ambassador wrote.
Cambodia also categorically rejected Thailand’s allegations concerning so-called newly planted Cambodian landmines, reaffirming its commitment to the Anti-Personnel Mine Ban Convention.
The letter said Cambodia’s commitment was rooted in both its treaty obligations and its own experience of the devastating humanitarian consequences of anti-personnel mines over decades.
It called for allegations of non-compliance to be supported by objective evidence, transparency and independent verification, reiterating Cambodia’s request for a joint, independent and impartial investigation.
Cambodia maintained that the convention’s compliance mechanisms should not be used as instruments of political pressure or to advance bilateral territorial disputes.
The ambassador also criticised Thailand’s use of historical events to justify what Cambodia described as present-day military incursions and continued occupation of its territory.
Cambodia called on Thailand to accept its repeated invitations to resume surveying and demarcation work through the JBC, saying the mechanism could help resolve outstanding boundary claims and establish a clear, mutually recognised border in accordance with international law and existing bilateral treaties and agreements.
The letter highlighted the humanitarian consequences of the border situation, stating that more than 20,000 Cambodian civilians remained unable to return home because of what Cambodia described as continued unlawful military occupation and obstructions, including barbed wire and shipping containers.
It also said maps annexed to the letter showed that the areas under Thai occupation extended beyond those depicted in Thailand’s unilateral maps.
Referring to the United Nations Special Rapporteur’s visit to the border in July, the letter quoted the official as saying that displaced residents “need, and deserve, to go home”.
Cambodia welcomed Thailand’s stated commitment to the ceasefire and the December 27 joint statement, but stressed that the commitment must be reflected in concrete action, including the resumption of JBC work and the cessation of unilateral activities that could aggravate the dispute.
It further called for activities in occupied areas that could create or consolidate a fait accompli to cease, describing this as a tangible demonstration of goodwill and respect for international law.
Addressing Thailand’s suggestion that Cambodia was seeking to internationalise the dispute, Ambassador Keo Chhea said Cambodia disagreed with that characterisation.
“Resort to mechanisms established under the Charter and treaties freely accepted by both States does not constitute an improper internationalization of disputes,” he wrote, adding that such action reflected the use of peaceful dispute settlement mechanisms recognised under international law.
The ambassador said Cambodia had been compelled to initiate compulsory conciliation proceedings under the United Nations Convention on the Law of the Sea after Thailand unilaterally terminated the 2001 memorandum of understanding in May, which Cambodia described as the only existing legal framework specifically established to address maritime disputes between the two countries.
Cambodia said the conciliation process offered an opportunity to bridge differences, rebuild trust and establish a stronger foundation for peaceful and constructive bilateral relations.
The letter also addressed Thailand’s stated aspiration to open a new chapter in bilateral relations, saying Cambodia shared that goal but maintained that it could not be achieved through competing narratives or unilateral actions.
It cited remarks by Thai Prime Minister Anutin Charnvirakul in May 2026 concerning the border situation, in which he reportedly said Thailand would not make concessions unless Cambodia conceded first and accepted Thailand’s conditions.
“Restoring trust must be grounded in concrete commitments,” Ambassador Keo Chhea wrote, urging Thailand to cease activities Cambodia considers unlawful, refrain from further unilateral actions and work to reduce tensions along the border.
Emphasising the geographical ties between the two countries, Cambodia said both nations would remain neighbours and that the peace, stability and prosperity of their peoples were closely interconnected.
Cambodia reaffirmed its commitment to resolving outstanding issues peacefully in accordance with the UN Charter, international law and existing bilateral agreements.
He requested that the letter be circulated as a document of the UN General Assembly under agenda item 8.
