South Korean soldiers advance during an assault on a position near Nha Trang in 1972 in Vietnam. South Korea was the second-largest foreign force in the conflict, which stretched from 1954-1975.
CNN  — 

Tran Thi Duoc was 16 when the soldiers came to her village.

They wore camouflaged uniforms and helmets and carried long, black rifles. Behind them, in a neighboring hamlet to the northwest, she and other villagers could see smoke from burning houses rising into the bright, midday sky.

The soldiers, who were Asian but spoke a language the villagers could not understand, ordered them to leave their houses and gather around a well in the village’s center.

Then the shooting started.

As Tran later told US military investigators, she fell to the ground and tried to play dead, but a soldier saw her and pulled her back up.

“I joined my two hands in front of my breast, knelt before him and begged for my life,” she said. “But he shot at me.”

The bullets broke her fingers and tore into her arms and upper body, but did not kill her. Tran passed out. When she woke up, she discovered her parents and two brothers dead, and her three-month-old sister wounded.

Tran Thi Duoc, then a 16-year-old resident of Phong Nhi village, testified to US investigators about the alleged massacre by South Korean troops. Original image altered for clarity.

In total, 69 people were killed in Phong Nhi and neighboring Phong Nhat that day in February 1968, according to a US investigation that was kept secret for decades.

It was one of many alleged Vietnam War atrocities committed against defenseless civilians that would come to be overshadowed by the My Lai massacre a month later.

Unlike My Lai, which became public the year after it happened, the Phong Nhi and Phong Nhat killings remained largely unknown until the 21st century.

They were also allegedly carried out not by US troops, but by South Korean soldiers, part of a pattern of brutal behavior documented in now declassified US government cables and reports, and the testimonies of survivors and veterans.

The revelations about South Korean atrocities during the Vietnam War, which began in the early 2000s, sparked a debate about the country’s culpability for the US-led conflict. This reckoning, which jarred with South Korea’s own history of abuse by foreign powers and mass killings, is still going on today and remains a deeply sensitive subject.

South Korea’s ‘crucial’ role

In September 1965, President Park Chung-hee, a former army general who had seized power in a coup four years earlier, ordered thousands of South Korean combat troops to pour into Vietnam.

They formed the bulk of of the Free World Military Assistance Forces, an unlikely grouping of troops from South Korea, Australia, New Zealand, the Philippines, Spain and Taiwan.

According to a 2016 report by the US School of Advanced Military Studies, “the ROK (Republic of Korea) Army played a crucial role in the US Army’s operations … and by 1972, outnumbered their American partners.”

Around 320,000 South Korean soldiers would rotate through Vietnam during the war, with more than 50,000 in the country at the height of their deployment, according to the SAMS report. Despite this, South Korea’s role in the conflict is little known in the West, where the Vietnam War is near universally depicted in popular culture as being fought by US troops, with other nations reduced to minor supporting roles.

South Korean soldiers seen with a group of captured Vietcong prisoners.

The deployment was a political masterstroke by Park, according to historian Kil J Yi, as it made the president essential to a US government that was balking at the cost of propping up a South Korean administration moving further from, not toward, democracy.

“South Korea was under enormous pressure to secure US economic and military assistance,” Yi told CNN. “The Vietnam War was the catalyst for Washington deciding to continue to pour massive aid into the Korean government.”

“South Korea’s participation changed how Washington perceived South Korea and (ROK) military forces,” Yi said, adding that in the wake of the war South Korea “became a model client state.”

A female Viet Cong soldier seen in action with an anti-tank gun during the Tet Offensive in early 1968.

Tet Offensive and brutal retaliation

South Korean assistance ramped up throughout the mid to late 1960s, but it did little to turn the tide of the war, and in early 1968, the North Vietnamese and their revolutionary allies in the South, dubbed the “Viet Cong” by the US, launched the devastating Tet Offensive, a massive surprise attack against 36 cities in South Vietnam, including the capital, Saigon.

In response, US, Free World, and South Vietnamese forces launched a brutal counteroffensive, one that was viscerally brought home to the US public when an AP photographer snapped Gen. Nguyen Ngoc Loan summarily executing an unarmed Viet Cong prisoner on the streets of Saigon.

According to Nick Turse, author of “Kill Anything That Moves: The Real American War in Vietnam,” the response to the Tet Offensive “quickly turned into an orgy of massacres.” Within months, the My Lai massacre would take place.

It was also at this time when a force of South Korean marines patrolling near the village of Phong Nhat (sometimes spelled Phong Nhut) came under sporadic sniper fire.