The Dangrek Incident, also known as the Preah Vihear Massacre, or Preah Vihear massacre, was the June 1979 systematic, forced repatriation of 42,000–45,000 Cambodian refugees (mostly women and children) by the Thai military. It resulted in from 3,000 to over 10,000 deaths from landmines, shootings, falls off cliffs, exposure, and disease. Transpiring near Cambodia's 11th–12th century Khmer Preah Vihear temple in the Dângrêk Mountains, Thai soldiers robbed the refugees before forcing them at gunpoint down a vertical cliff, through and into active minefields the military were aware were present. Thai soldiers carried out mass shootings against groups and individuals who refused to descend or attempted to climb back to escape the minefields. Thousands of refugees who survived the initial descent remained trapped in minefields below the cliff into July, where more perished.
In January 1979, Vietnam overthrew Pol Pot's deadly regime in Cambodia, forcing the Khmer Rouge west where they were supported by Thailand at its border. Confronted with a country in ruins and also a famine, an estimated 140,000 Cambodian refugees fled to Thailand between the spring and early fall of 1979. Between approximately June 8th and June 15th of 1979, Thai soldiers used deception and violent coercion to corral Cambodian refugees from multiple encampments onto the buses bound for Preah Vihear, to be marched through minefields back into Cambodia. Some refugees were rescued before the buses drove off, and the Thais refused to halt the process.
Thai officials defended the operation as a national security move in response to a lack of resettlement assistance from Western nations, and insisted the Preah Vihear area offered the best chance for survival despite acknowledging there were boobytraps and landmines. US embassy staff and United Nations High Commissioner for Refugees workers later acknowledged their failure to act or attempt any meaningful protest. UNHCR official Dennis McNamara called the failure a "low" point in the agency's history. Some survivors went on to share their experiences in books, and the first film to document the atrocity, called Ghost Mountain: The Second Killing Fields of Cambodia, was released in 2019.
Production on a second film began in January of 2026. Directed by Leak Lyda, Blood Border: Cambodia's 2nd Killing Fields will be released in Cambodia in November of 2026.
Background
Vietnam War spillover
During the Vietnam War, Thailand’s military government allowed access to Thai airbases from which the United States bombed Indochina, including locations within Cambodia. The USA pumped $1.1 billion+ in economic and military aid into Thailand, along with the construction of infrastructure connecting Thai cities to the countryside. At the war’s peak, about 50,000 US military personnel were stationed in Thailand.
From 1969 to 1973, the United States heavily bombed neutral Cambodia, an operation authorized by US president Richard Nixon and Secretary of State Henry Kissinger that was initially not disclosed. The bombing’s devastation, and then the subsequent April 1970 US ground invasion into eastern Cambodia, disrupted rural life and displaced over a million Cambodians.
The destruction and civilian casualties destabilized Cambodia, and was weaponized by the Khmer Rouge to radicalize rural Cambodians. The once-small guerrilla faction grew into a large army that seized control of the country on April 17th, 1975.
Vietnam invades Democratic Kampuchea
On 25 December 1978, supported by exiled Cambodian dissidents, Vietnam invaded Kampuchea (Cambodia) and captured capital Phnom Penh within weeks. Ousted and driven into the northwest area bordering Thailand were the Khmer Rouge, whose regime caused the deaths of up to 2.8 million Cambodians from exhaustion, starvation, disease, lack of medical care, or execution. Thailand viewed Vietnam's victory as a political threat and strengthened ties with the Khmer Rouge and China, a Khmer Rouge ally opposed to Vietnam. Thailand allowed a weapons flow from China to the Khmer Rouge, who funded themselves by smuggling gems and timber across the Thai border. China in turn ceased support for Thai communists and awarded the Thai military with cheap arms. The ousted Khmer Rouge were permitted entry into Thailand to escape and recover from attacks by the Vietnamese, before returning to Cambodia. The entry of civilian refugees was blocked as much as possible.
Most Cambodian survivors of the Khmer Rouge had lost family and most personal property, their homes, and had no means of survival. Some feared further persecution from the Vietnamese whom they perceived as a historical enemy. Now also facing famine, hundreds of thousands of Cambodians fled as 1979 advanced, seeking refuge at the Thai border. Thailand laid land mines to stop the anticipated influx of Cambodian refugees, then closed its borders, prompting refugees to gather in camps dotting the Cambodian side. Thailand's approach to Cambodian refugees was harder than to Hmong, Lao, Vietnamese, and Sino-Vietnamese due to a perception that "millions" could arrive.
Denial of refugee status
The UNHCR and scholar-practitioner Dr. Fiona Terry reported that between April 21st and 26th of 1979, 6,000 Cambodian refugees were pushed back to Cambodia from Ta Phraya district in Thailand by authorities. Dr. W. Court Robinson wrote that an additional 1,700 Cambodian refugees were pushed back in April from Aranyaprathet's Wat Koh area.
On May 5th, former New York Times foreign correspondent Henry Kamm reported that 200 "wan and apathetic" starving Cambodian refugees, mostly women and children, would be pushed back to Cambodia to "nearly certain death within seven days." In Ban Laem, a poor village about 50 miles northeast of Chanthaburi, Thai military authorities decided the refugees were healthy enough to be expelled back to Cambodia, despite acknowledging they may be killed by the Khmer Rouge. Officially no Cambodian refugees were to be forced back involuntarily, in practice Thai military officials said all Cambodian refugees would be denied refuge and pushed back to Cambodia. Thai military sources referred to foreigners opposed to this as "bleeding hearts." Thailand refused to recognize the fleeing Cambodians as refugees despite the UNHCR's offer to fund food for Cambodian refugees permitted entry. The Thai official said the refugees' fate was not a concern, adding, "I don't care. But if the American Embassy wants to come here and take them to America, they can."
Between the 18th and 23rd of May, some 1,000-3,000 more Cambodian refugees were pushed back to Cambodia from Nong Chan, north of Aranyaprathet. During a three-week pause on push backs, a minimum of 15,000 Cambodian refugees entered Thailand. This pause from late April to mid-May may have been performative as Secretary-General of the United Nations Kurt Waldheim was scheduled to visit in May. Once Waldheim arrived, the International Committee of the Red Cross (ICRC) and UNHCR convinced him to visit the refugees camped at Wat Koh. In response to pleas from the loved ones of refugees pushed back in April, Waldheim tried convincing Thai prime minister Kriangsak Chamanan to allow the refugees to remain.
Rumors and New York Times report
On June 5, Frenchwoman Yvette Pierpaoli traveled to the border from her Bangkok home upon rumors Thai officials planned to forcibly repatriate a large number of Cambodian refugees. Seeing Cambodians detained behind barbed-wire, she returned to Bangkok to organize an emergency response. British journalist and former foreign correspondent William Shawcross wrote that 110 buses arrived early Friday June 8th to a Cambodian refugee border encampment at Nong Chan. Thai soldiers told refugees they'd be moved to another camp; some refugees didn't believe this. Emptying the camp took three days and then Thai officials continued to other sites.
On June 12th, Henry Kamm reported that over the previous days, Thai officials bused tens of thousands of Cambodian refugees to the Preah Vihear area of the Dangrek Mountains to be forced at gunpoint down a cliff back into Cambodia. A Thai military officer said that more present and arriving Cambodian refugees would be forced back the same way. The officer said this area was the best chance for survival, then acknowledged the presence of "mines and booby traps" that cause casualties.
Protest and rescue attempts
The Thais arrived with Preah Vihear-bound buses to corral the Cambodian refugees at Aranyaprathet's Wat Koh area. Relatives of many refugees contacted their embassies after hearing that family members, whom they had just learned had survived the Khmer Rouge, would now be forced back into Cambodia. French journalist Roland‐Pierre Paringaux reported that a Khmer New Zealander trailed a convoy carrying a dozen of his family members with documentation securing their safety. He pleaded with the Thai officers at each stop before his family was driven off to Preah Vihear.
On June 12th, barb-wire blocked Pierpaoli, American diplomat Lionel Rosenblatt, John Crowley, and Rich Kocher from the Buddhist temple Wat Koh's enclosure, where "panic-stricken" Cambodian refugees were held, when they arrived with buses in a rescue-attempt. For three hours, from outside the camp, they read names aloud from a list of refugees approved for resettlement. There were translation problems reading the names and some named refugees were skeptical, while others trusted the foreigners over the Thai soldiers. The foreigners also "picked out" refugees. Noticing the one soldier near her, Pierpaoli "simulated a dead faint" into his arms, the distraction allowing a woman and child to board the foreigners' bus and three male refugees to run off. 1,500 listed refugees were saved; most refugees listed were taken to Preah Vihear. The Thais expelled the foreigners, and informed refugees they'd be transported to resettlement camps. Thai soldiers used physical violence to force a number of refugees onto the buses.
Pierpaoli, Rosenblatt, and others brought the rescued Cambodian refugees to Bangkok's Lumpini Transit Center. The Thais initially objected so USAID worker MacAlan "Mac" Thompson got the officials drunk and they relented. Thompson also attempted to trail the buses and was stopped by a Thai Army roadblock, though he correctly reported to Rosenblatt that the caravan was headed towards Preah Vihear.
International Committee of the Red Cross (ICRC) delegation head Francis Amar protested a day after the first group was taken to Preah Vihear, saying the refugees may die or end up in the same situation that first led them to flee. As a consequence, Amar was forced to return to Geneva, and replaced.
Massacre at Preah Vihear
Forced descent at gunpoint
After 14 hours, the buses arrived to the Preah Vihear area in the dark. The Thai forces secured the spot from any possible outside observation. Children and women were the majority of passengers. The Thais handed out small amounts of rice, and then told the refugees: "Thai money will not be valid in Kampuchea. We ask you make a voluntary contribution to our military." Thai soldiers confiscated money and personal property they discovered on the refugees.
At gunpoint, refugees were forced to descend a mined trail "down the nearly vertical mountainside," into the minefield that lay at the foot. Refugees were told they'd run into Vietnamese soldiers at the other end. The Thai military was aware there were mines in the path.
Mass shootings and landmine detonations
Shawcross reported that a group of refugees combined their valuables and held a white flag while returning towards Thai soldiers, who then took the items before they "opened fire on" the group. In what she calls the Preah Vihear Massacre, Dr. Khathaleeya Liamdee reported that those who refused to descend were shot. In To Bear Any Burden by Al Santoli, survivor Kassie Neou reported that Thai soldiers shot and killed a widowed mother who begged to stay. According to Neou, after soldiers ordered someone to take the woman's baby "out," he then discovered the deceased infant on a rock as he descended the cliff, and noted that a whole family had been killed.
Neou further reported hearing explosions regularly as he climbed down the cliff with his children. He "walked over" a separate pile of bodies belonging to an entire family, including parents, a grandmother, an uncle, and multiple infants, noting that another entire family had also been killed. Many attempting to return were shot and killed by Thai soldiers. In her oral history and memoir, survivor Teeda Butt Mam describes witnessing two boys attempting to fight their way back up the overhanging cliff. According to Mam, Thai soldiers shot one child between his eyes and shot the other child's head off, causing her young nephew to drop his bag of rice. Thompson reported that former Lon Nol soldiers were the first forced down. Once their bodies cleared a path through the minefield, refugees behind them "stepped over" the dead. According to Neou, most dead in the minefields belonged to the people forced down on June 8th; the refugees in his group walked in each other's footsteps.
Dr. W. Courtland Robinson wrote that approximately two-thirds of the refugees were ethnic Chinese.
Survivors stranded in minefields
Some 10,000 Cambodian refugees remained trapped in the minefields beneath Preah Vihear for over a week, into July. According to Teeda Butt Mam, the refugees "lay beside, stepped over, ate near, and slept with the mutilated dead" while trapped in the minefields. Refugees were fearful of setting off the mines if they resumed their journey. Water and food were scarce, and some refugees who ventured out in search of food and water were killed by landmines. Refugees hunkered against the mountains survived on rice sold at "usurious prices" by Thai soldiers. Some refugees received food sent by Vietnamese soldiers through de-mined trails. Some survivors were led to safety by Vietnamese soldiers. Traversing the minefields took three days, and when some survivors attempted to return to Thailand, they were shot by Thai soldiers. Some refugees died of disease and exposure.