For more than five years, the U.S. Army brushed aside allegations of a massacre of civilians during the early days of the Korean War and claims for compensation by survivors, despite strong circumstantial evidence in its own files that lends credence to the assertions.

Earlier this week, several former American soldiers ended a half century of silence about the alleged atrocity and talked about machine-gunning hundreds of Korean refugees trapped under a railroad bridge near the South Korean village of No Gun Ri in July 1950. Their testimony, first reported by the Associated Press, has led Secretary of Defense William S. Cohen to order a full investigation into the actions of units of the 1st Cavalry Division and reexamine claims for compensation.

Describing the reports of the incident as "very disturbing," Secretary of the Army Louis Caldera yesterday promised "a thorough review" of the allegations, including extensive interviewing of former GIs. In a letter to Caldera, Cohen called for "whatever resources are appropriate to accomplish this review as thoroughly and as quickly as possible."

Survivors of the reported massacre said they were afraid to air their grievances under the U.S.-backed authoritarian regimes that ruled South Korea but began petitioning President Clinton and other U.S. officials from July 1994 onward. Representatives of the survivors said that some of their letters were ignored, while others were met with polite rebuffs. On one occasion, in 1997, the U.S. Armed Forces Claims Service in South Korea wrote to the representatives to say that the 1st Cavalry Division was not even in the area of No Gun Ri when the incident occurred.

However, Army records at the National Archives at College Park corroborate many of the details provided by the South Korean survivors, including the presence of 1st Cavalry units in the vicinity of No Gun Ri and the strafing of the railroad by U.S. military aircraft. While there is no document that describes the machine-gunning of civilians underneath the railroad bridge, there are copies of orders authorizing commanders to fire on refugees and details of troop movements that are generally consistent with the claims of the survivors.

The archives paint a vivid picture of the problems confronting the Army in July 1950 as it fell back in full retreat through the Korean city of Yongdong only days after being rushed to Korea to help the allied South Korean army withstand a full-scale communist offensive. The communists frequently resorted to the tactic of infiltrating their guerrilla soldiers into large groups of fleeing refugees. Once they had succeeded in passing through U.S. lines, the guerrillas would attack the Americans from the rear, spreading panic among the raw GIs.

The 1st Cavalry War Diary, dated July 24, 1950, refers explicitly to the difficulty of controlling the refugee flow. "No one desired to shoot innocent people, but many of the innocent-looking refugees dressed in the traditional white clothes of the Koreans turned out to be North Korean soldiers transporting ammunition and heavy weapons," the diary says. "There were so many refugees that it was impossible to screen and search them all."

The records show that the previous day a general order was issued to all three regiments of the 1st Cavalry Division: "No refugees to cross the front line. Fire [on] everyone trying to cross lines. Use discretion in case of women and children."

While the Army records are incomplete and leave many questions unanswered about what happened in No Gun Ri, they provide many clues for further research, including the names of soldiers who were in a position to know what happened. But when Army historians looked into the atrocity allegations earlier this year, they limited themselves to reviewing the documentary evidence and did not attempt to track down former GIs.

On March 22, the Pentagon wrote a letter to the claimants' American representative, the U.S. Council of Churches, saying that its research had "produced no evidence to demonstrate U.S. Army involvement" with the deaths of the villagers.

As the 50th anniversary of the Korean War approaches, many veterans resent the sudden highlighting of an alleged U.S. atrocity. "You always get [atrocity] stories like this in a war," said former lieutenant William Kaluf, whose platoon was stationed near the railroad bridge where the killings allegedly occurred. "It was the same thing at the Battle of the Bulge [in World War II]. My opinion is that the stories don't mean zilch."

One of the American soldiers involved in the No Gun Ri incident, retired machine-gunner Edward L. Daily, said he felt the need to speak out even though many of his old Army buddies had urged him to keep quiet. "It's a form of mental cleansing," he said. "If you keep hiding the truth, it just creates more problems."

Daily served with H company of the 1st Cavalry Division's 7th Regiment, which was stationed roughly 150 yards from the railroad where the refugees came under fire. He says that several hundred refugees sought cover under a railroad trestle after being strafed from the air by U.S. warplanes on July 25 and 26.

"We got orders to shoot them all," he recalled. "The officers thought there were guerrillas hidden among the refugees, and the easiest way of dealing with the problem was to shoot them all."

Detailed unit reports for H company have not survived, and there are no entries in the 7th Regiment war diary for the crucial period from July 26 to 28. But there are scraps of evidence in the archive that appear to corroborate the accounts of Daily and other eyewitnesses. An intelligence report filed among the 1st Division records refers to a P-80 warplane "with allied markings" strafing the railroad in the vicinity of No Gun Ri on the morning of July 25.

The regimental war diary also contains a detailed description of an apparently related incident in the early morning hours of July 25 that resulted in only minor casualties. It describes how U.S. troops "fired a volley of small arms and machine gun fire" into a group of Korean refugees on the assumption that they were "enemy." The civilians were later "rounded up" and permitted to pass through U.S. lines, the diary recorded.

Caldera described the early weeks of the Korean conflict as "very chaotic" and described the U.S. soldiers as "ill-trained" and "ill-equipped," a judgment shared by many military historians and former officers. Col. Julius Schrader, who served as a platoon leader with the 7th Regiment, said his troops included petty criminals who had been given a choice between "going to jail and going into the army."

In reply to a question, Caldera said the United States would consider paying compensation to Korean victims "if the review shows that something that was inappropriate did occur." In the past, U.S. military officials in Korea have turned down requests for compensation on the grounds that the statute of limitations has expired.

Some U.S. Korean veterans said they would oppose compensation. "I take a dim view of that," Schrader said. "Everybody was shooting everybody. We had our own people getting killed by our own side."