Six years after declaring the U.S. killing of Korean War refugees at No Gun Ri was"not deliberate," the Army has acknowledged it found but did not divulge that a high-level document said the U.S. military had a policy of shooting approaching civilians in South Korea.

The document, a letter from the U.S. ambassador in South Korea to the State Department in Washington, is dated the day in 1950 when U.S. troops began the No Gun Ri shootings, in which survivors say hundreds, mostly women and children, were killed.

Exclusion of the embassy letter from the Army's 2001 investigative report is the most significant among numerous omissions of documents and testimony pointing to a policy of firing on refugee groups -- undisclosed evidence uncovered by Associated Press archival research and Freedom of Information Act requests.

South Korean petitioners say hundreds more refugees died later in 1950 as a result of the U.S. practice. The Seoul government is investigating one such large-scale killing, of refugees stranded on a beach, newly confirmed via U.S. archives.

No Gun Ri survivors, who call the Army's 2001 investigation a"whitewash," are demanding a reopened investigation, compensation and a U.S. apology.

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Text of U.S. ambassador's 1950 refugee letter