Prime Minister Hun Sen yesterday used the 40th anniversary of his defection from the Khmer Rouge to re-enact his crossing into Vietnam, justify his decision to join the brewing plot by Cambodia’s historical enemy to overthrow Pol Pot’s bloody regime and warn his present-day enemies to “prepare their coffins”.

Arriving by helicopter at about 7am in Koh Thmor in Tbong Khmum’s Memot district, Hun Sen began the ceremony by recounting his fateful decision to abandon the communist regime he helped bring to power in 1975 and said it was not easy to leave his wife behind to try to build a force to overthrow Pol Pot.

Dressed in military uniform and flanked by government ministers, senior military generals including Deputy Commander in Chief Kun Kim and other allies, the prime minister recounted the “difficult” decision in 1977 to defect from the Khmer Rouge amid mass purges and seek safety in Vietnam.

“At the beginning I found it difficult to find the words. I sobbed alone at my room. How do I tell my wife?” Hun Sen said, referring to a letter explaining his decision he wrote to Bun Rany, and also noting Prince Norodom Sihanouk and Lon Nol before him had sought help from the Vietnamese when they were in power.

Apart from recounting his decision to defect from Pol Pot’s regime, Hun Sen also sought to clarify why he turned to Vietnam. Many among the opposition have characterised the premier as a “puppet” of Hanoi, who installed him as prime minister in 1985.

“I could not pick Thailand or Laos because both countries were far from the location that I was living in, and I was not sure that those countries could help Cambodia,” he explained.

Prime Minister Hun Sen has an emotional moment, as he retells the story of his defection from the Khmer Rouge. Pha Lina

Less than two years after Hun Sen’s June 1977 crossing into Vietnam, he returned to Cambodia as one of the key founding members of the new Hanoi-backed People’s Republic of Kampuchea regime, for which he initially served as foreign minister.

Koh Thmor village’s 300 residents – mostly from the Stieng ethnic minority – attended. Each family received 50 kilograms of rice, fish sauce and instant noodles – gifts from the premier to mark the occasion. Most had scurried to get a glimpse of him in the morning as he descended from his helicopter.

As his speech wound down, Hun Sen also made small talk with many of the villagers. He asked them if they had any problems he could have fixed, cracked a few jokes and eventually even agreed to install a power generator in the village, build a small religious shrine there and complete an unfinished school.

Then began a 7-kilometre drive involving more than a hundred cars and buses to the Cambodian-Vietnamese border, where he on June 21, 1977, crossed into Vietnam. While his two-hour-long speech in Koh Thmor had been mostly sombre, standing at the border the premier took on a more bellicose tone. After paying tribute to his companions on his trek into Vietnam – Nuch Thorn, Va Por Ean, Nhek Huon and Sou Kim Sreang – he suddenly took a sharp turn in his mood to quell any confusion about his recent warnings of renewed war and appeared to directly threaten to kill present-day political opponents.

“Your tongues will be the motive for the war,” Hun Sen said, in an apparent reference to the opposition. “If you all keep talking about insults and the threats to kill, you all must prepare your coffins already. I warn that Cambodia will not lose peace.”

He also sought to further clarify comments made before the June 4 commune elections that he was prepared to “eliminate 100 or 200 people” to ensure the stability of Cambodia. There should not be any confusion about who he meant, he insisted.

“My answer is that if you are in the group destroying peace, you are also among 100 or 200,” he said. “You listen: If you grab power with a colour revolution, you are on the list.”

Following his comments, most of the delegation walked across the border to a waiting convoy to continue the tour into Vietnam. However, Hun Sen himself traversed a path covered with wooden boards, continuing his re-enactment of the crossing.

Prime Minister Hun Sen speaks at an event yesterday to mark the 40th anniversary of his defection from the Khmer Rouge in an event held yesterday in Tbong Khmum province.Pha Lina

He occasionally stopped to talk about where he had slept on a hammock after getting about 200 metres into Vietnamese territory. On the Vietnamese side he was welcomed by a delegation before heading to the next part of his journey to Vietnam.

Ou Virak, head of Future Forum, said Hun Sen had now put the Vietnamese link to his defection and overthrow of Pol Pot on the political table ahead of next year’s important national election – an attempt, he said, to reclaim the mantle of nationalism.

“The opposition claims they are the nationalists. But it is very difficult to pull it off” for the prime minister, Virak said.

“There might be credit for ending or leaving the Khmer Rouge but he was in the Khmer Rouge. He doesn’t want it to be raised, but this event will raise more questions than answers.”