SEOUL, South Korea — In the opening months of the Korean War, the South Korean military and the police executed at least 4,900 civilians who had earlier signed up — often under force — for re-education classes meant to turn them against Communism, the country’s Truth and Reconciliation Commission announced Thursday.
The government killed the civilians out of fear that they would help the Communists who were invading from the north and forcing South Korean and American forces into retreat during the first desperate weeks of the war, the commission said.
Although the panel has reported on similar civilian massacres in the past, the announcement Thursday represented the first time that a state investigative agency confirmed the nature and scale of what is known as “the National Guidance League incident” — one of the most horrific and controversial episodes of the war.
The anti-Communist and authoritarian government of President Syngman Rhee had set up the league to re-educate people who had disavowed Communism in the months before the war, and forced an estimated 300,000 South Koreans to join. At the time, the government was facing a vicious and prolonged insurgency by leftist guerrillas.
But the commission reported that many of those who joined the league had never been Communists. They either were swept up because they had provided food or other aid to Communists hiding in the hills, often at gunpoint, or were required to join by local officials seeking to meet a government quota for the number of Communists being re-educated. In some instances, the panel said, peasants were lured into joining with promises of bigger rice rations.
“The authorities pressed us to join the league,” said Kim Ki-ban, 87, at a news conference called by the commission on Thursday. “We had no idea that we were joining a death row.”
Mr. Kim, who at the time was a villager in Cheongwon, 60 miles south of Seoul, said that he and more than 60 other league members had been locked up in a warehouse in the second month of the war, but that he escaped during the confusion caused by an allied aerial bombing. The next day, he said, all the others were shot to death, their hands tied behind their backs with wire.
As with many of the other victims of government massacres during the war, which started in June 1950, discussion of the fate of the league members was taboo during the postwar decades of military rule.
“Given the number of victims and unlawfulness, this is the worst tragedy of 20th-century South Korea,” Kim Dong-choon, a commission member, said at the news conference.
The commission, established in 2005, said that it believed thousands more civilians died in the league killings but that it was afraid the true scale might never be known because it feared that President Lee Myung-bak would scale back its investigations.
Mr. Lee won the presidency in 2007 with the support of conservatives who denounced the commission’s work as dividing South Korean society at a time when Communist threats from North Korea were continuing.
The commission said it could identify only 4,934 victims so far and could not confirm who had ordered the systematic, nationwide killings, though Mr. Kim suggested that the orders came from the “top” of the government.
During decades of military rule in postwar South Korea, the families of many victims remained silent, branded untrustworthy members of society. Even as the panel began its work, many were afraid to come forward.
Efforts to peel back the long-running cover-up were a hallmark of pro-democracy activists who struggled against past military dictators. But conservatives saw these efforts as a leftist political maneuver to discredit their achievements, especially their vigilance against the Communist North.
Many former police and military officers refused to cooperate with the commission, which had no power to compel testimony or indict. But others broke the silence.
Lee Joon-young 85, a former prison guard who witnessed assembly-line-like executions near Taejon, south of Seoul, in July 1950, was one who stepped forward.
“Ten prisoners were carried to a trench at a time and were made to kneel at the edge,” he said in an interview. “Police officers stepped up behind them, pointed their rifles at the back of their heads and fired.”
Another man, Choi Woo-young, 82, a former police officer who supervised 59 league members in the southern town of Hapcheon, said the civilians did not deserve to die. “They were not a threat to the government,” he said.
On July 31, 1950, Mr. Choi said, his police contingent was ordered to kill all league members before retreating. But he saved them, he said, when he secretly alerted them not to heed a police siren that was supposedly signaling them to gather for another session of “re-education.”
The police had regularly used sirens to gather league members for re-education classes or just to ensure that they had not fled to join the Communists. When they were called to gather for the last time, many did not suspect that they were going to be detained for up to several months and, in many cases, to be executed, survivors said.
On Thursday, the commission unveiled old government documents that contained partial lists of league members who had been killed. Documents showed that the police kept surveillance on the league members’ relatives as late as the 1980s to ensure that their children did not get government jobs, the panel said.
A national association of victims’ families lamented that the commission had revealed only “the tip of an iceberg” and demanded that the commission’s term, which ends next spring, be extended.