A Cambodian minister put the An Seh case on Facebook on 29 August 2026, resting it on treaties of 1904 and 1907 and on Thailand’s own military map. Thailand’s border spokesman had refused that word on 26 August, and its foreign ministry had published a legal basis for the same crossing on 11 March.
Cambodia’s Minister of Information, Neth Pheaktra, posted the message on Facebook on 29 August 2026. The state news agency carried the full text that day and called it a Facebook message, not a ministry release. His own ministry published the Khmer original on its website.
Cambodia calls the place An Seh and puts it in Choam Ksan district, Preah Vihear province. Thailand calls it Chong An Ma and puts it in Ubon Ratchathani province. Thailand’s foreign ministry writes the two names as one pair, the An Mah-An Ses point of entry. Both governments agree the Thai prime minister stood there on 23 August. They do not agree whose ground it is.
The message asks whether Thailand holds any map, treaty or legal basis putting that crossing under Thai sovereignty.
Thailand published one on 11 March 2026. Its foreign ministry named the crossing. It said Cambodia had built a market and a monument on land encroaching the Thai side of the watershed there. A watershed is the ridge where rainfall divides between two river systems. The International Court of Justice recorded in 1962 that the Franco-Siamese treaty of 1904 set the frontier along the watershed in this stretch of the range.
That statement came five months before the minister asked his question. In the same paragraph the ministry invoked Article V of the memorandum the two countries signed in 2000 on surveying and marking their border. Article V binds both governments. Neither may do work that changes the environment of the frontier zone, as Thailand told the Security Council in 2008. The text does not say where that zone starts or ends.
The message points to sheet 5937 I of series L7017, a Thai army map made by Thailand’s own survey department at 1:50,000 scale. It says that sheet puts the site on the Cambodian side. The sheet is not in this record. What is in it is a fragment, published by Cambodia with the article, beside a satellite image. Neither graphic carries a credit. The lines and the markers on them are drawn by a hand no page names.
On the drawings, two boundary lines run close together through the crossing. One is labelled as copied from a 1:200,000 map, where a centimetre of paper covers two kilometres of ground. The other is labelled as the line of Thailand’s own 1:50,000 series, where a centimetre covers half a kilometre. Both visit markers sit on the Cambodian side of both lines. That is what the drawing displays. What the sheet itself shows is a second claim, and it is open.
The message also says, in Khmer and in English, that Thailand called the prime minister’s unauthorised entry not an act of boundary demarcation. Demarcation means putting the line on the ground with pillars. Thailand said half of that. On 26 August the director of Thailand’s Joint Information Centre, the body that speaks for the Thai government on the border, said visiting troops is not demarcation. He refused the other half. The word unauthorised, he said, is one side’s own word, and it settles nothing about sovereignty.
Containers are not boundary pillars, the same director said. Barbed wire is not a treaty. Trenches are not a boundary map. On that, he said, the Cambodian side is right. Matichon dated those remarks 25 August and Thai Post dated them 26 August. He concedes wording, not the line. He asked both sides to open the evidence at the Joint Boundary Commission. That is the body the two governments built to survey the border and mark it.
The Joint Statement they signed on 27 December 2025 told that commission to resume the survey and the marking at the earliest, and to put the border areas where civilians lived first. People live on both sides of this crossing, beside a line that has never gone into the ground. This record does not show the commission meeting since. How many live within reach of it, and what the delay has cost them, are not in this record.
The minister puts Cambodian proposals to convene the commission at nine. Three carry dates here: 28 December 2025, 5 January 2026 and 7 April 2026. A further round in June is recorded only as repeated. Thailand has published reasons. In March its foreign ministry said it would answer once the new cabinet was formed, and that survey work could not go ahead while the survey team was in danger from landmines.
The message rests part of its case on Point 3 of that Joint Statement. Paragraph 3 says every arrangement made under the statement is without prejudice to demarcation and to the international boundary. On 26 August Thailand’s foreign ministry said the prime minister had visited Chong An Ma on the Thai side, in strict conformity with the same statement. That paragraph stops the text placing the visit. It stops Point 3 carrying a claim of title in the same words. What Thailand said that day is about the visit and reaches nothing else in the dispute.
The International Court of Justice ruled in 1962 that Prasat Preah Vihear stood on Cambodian ground. In 2013 it read that ruling as covering the promontory of Preah Vihear and nothing beyond it. Neither ruling reaches this crossing. Two bodies could fix the line here, that court and the commission the two sides built for it. Neither has.
Set the two texts of the message side by side and the English is the softer one. Where the Khmer says flatly that Cambodia’s commission asked to meet no fewer than nine times, the English adds that Cambodia says so. The Khmer closes its protest paragraph with a clause the English drops, about Thai forces wrecking civilian buildings and creating facts on the ground. That comparison is this desk’s own. On 27 August the minister credited the location finding to the State Secretariat of Border Affairs. On 29 August he asserted it himself.
