, the disputed temple
Colonial period The boundary area has historically switched back and forth between various Khmer and Thai empires. In 1867 a Franco-Thai treaty confirmed Thai ownership of the
Battambang and
Angkor (Nakhou Siemrap) regions. A
Cambodian–Thai border dispute arose in the late 1950s over the ownership of
Preah Vihear, a temple in the Dângrêk Mountains, adjacent to the border. The mid-1960s also saw a dispute over ownership of
Ko Kut island. Sporadic
fighting broke out along the border following Vietnam's
invasion of Cambodia in 1979 which forced the Khmer Rouge to flee to camps on the border with Thailand, using them as a base throughout the 1980s until Vietnam withdrew from the country in 1989. On 18 February 1994, the Khmer Rouge led by
Pol Pot (
Saloth Sâr) rebuilt their headquarters at
Dângrêk Mountains located in
Anlong Veng near the Thai border. In an effort to stop Khmer Rouge infiltration from Thailand, Cambodia built a large
fortified fence along the border in the second half of the 1980s. Since the advent of peace in Cambodia in the early 1990s relations with Thailand have once again soured over the Preah Vihear issue, as well as, to a lesser extent, Ko Kut island. Armed fighting broke out at various times
from 2008 to 2011. As of September 2022, government officials said border demarcation had been completed in 13 areas, and that the remaining 11 were under negotiation. On 28 May 2025, one
Royal Cambodian Army soldier was killed after a Thai patrol encountered Cambodian soldiers digging trenches. Both Cambodia and Thailand accused the other of trespassing on their respective territories and firing first.
Phumtham Wechayachai, Thailand's Defense Minister, claimed that opening fire was not intended on both sides. Cambodia stated that it will litigate the dispute with the
International Court of Justice. In July 2025,
the conflict was reignited with both sides' military attacking each other. Thailand also sealed all land border crossings with Cambodia. Multiple civilians were reported to be killed. On 24 July 2025, Cambodian Prime Minister
Hun Manet submitted a request to the United Nations Security Council to call for an urgent meeting to stop Thai aggression. The UNSC held the meeting on 25 July 2025. With mediation effort from 2025 ASEAN Chair country Malaysia, as well as call for a ceasefire from U.S. President
Donald Trump to both countries, Hun Manet and Thailand Acting Prime Minister
Phumtham Wechayachai met in Kuala Lumpur for peace talks on 28 July 2025. Both countries agreed on an immediate and unconditional ceasefire taking effect on on 29 July 2025. On 8 December 2025, after both countries reported violations of the ceasefire, fighting across the border resumed until another ceasefire agreement was signed on 27 December. ==Border crossings==