Newly declassified documents show that the United States knew
immediately after the Korean War that North Korea had failed to
turn over hundreds of American prisoners known to be alive at
the end of the war, adding to growing speculation that American
prisoners might still be alive and in custody there. The
documents, obtained from the Dwight D. Eisenhower Presidential
Library and other Government depositories by a Congressional
committee, show that the Pentagon knew in December 1953 that
more than 900 American troops were alive at the end of the war
but were never released by the North Koreans. The documents may
only deepen the mystery over the fate of Americans still
considered missing from the Korean War. In June a Defense
Department intelligence analyst testified that on the basis of
''a recent flurry'' of ''very compelling reports,'' he believed
that as many as 15 Americans were still being held prisoner in
North Korea. While not dismissing the analyst's report entirely,
the Defense Department has said i