Foreign Ministry spokesman Nikorndej Balankura issued the statement on Sunday, following a blast that injured three Thai soldiers near the Chong Bok border area in Ubon Ratchathani province on July 16.
Citing reports from security agencies, the spokesman said inspections had confirmed that the landmines used in the incident were newly planted and not part of Thailand’s arsenal or inventory.
Evidence gathered from the blast site, along with environmental factors, led officials to conclude that the incident constituted a serious violation of international law.
“The Thai government condemns in the strongest terms the use of anti-personnel landmines. Such actions violate Thailand’s sovereignty and territorial integrity and are in direct contravention of the fundamental principles of international law as stated in the United Nations Charter,” Nikorndej said.
He added that Cambodia’s actions also clearly breach obligations under the Anti-Personnel Mine Ban Convention, to which both Thailand and Cambodia are state parties.
Thailand, he affirmed, would address the matter through existing bilateral mechanisms and called on Cambodia to cooperate in mine clearance operations along the border, as previously agreed upon by the two prime ministers.
Nikorndej also revealed that on the afternoon of July 20, the secretariat of the Ad Hoc Centre for the Thailand-Cambodia Border Situation met to exchange and prepare information ahead of a high-level meeting scheduled for July 21.
He stressed that the issue involves multiple legal and diplomatic frameworks and must be handled with caution. “This is a sensitive moment. Public messaging, especially on social media, must be responsible to avoid misunderstandings or unintentional divisions,” he said.
He urged the public to trust the work of government and security officials and emphasised that national unity was of utmost importance.
In a separate statement, the Thailand Mines Action Centre (TMAC) expressed deep concern over the July 16 incident, confirming that unauthorised actors had planted anti-personnel mines in Thai territory near Chong Bok.
Three Thai soldiers were injured, one of whom suffered life-altering injuries resulting in permanent disability.
TMAC’s explosives experts confirmed that the mines used were newly placed and of a type not in use by the Thai military. The area appeared to have been deliberately laid out as a minefield, posing significant danger to security personnel and civilians alike.
The centre condemned the act as a grave breach of the Mine Ban Treaty, also known as the Ottawa Convention, which prohibits the use, stockpiling, production, and transfer of anti-personnel mines.
TMAC stressed that both Thailand and Cambodia are parties to the treaty and have committed to ending the use and stockpiling of such weapons, as well as to clearing mines within their territories.
TMAC urged the Cambodian government to take clear and concrete responsibility for the incident. It called for a full and transparent investigation, legal action against those involved, and meaningful steps to prevent similar incidents in the future.
Furthermore, TMAC called on Cambodia to cease obstructing Thai demining efforts along the border and to actively cooperate in humanitarian mine clearance operations. This, the centre said, would ensure safety and build trust among communities on both sides of the border.
“It is also a matter of joint responsibility under the Ottawa Convention to support peace, human security, and reduce the indiscriminate threat posed by landmines,” TMAC said.