Updated

MOSCOW (AP) — A top Russian official says there's no legal basis for reopening an investigation into the Katyn massacres, when thousands of Polish officers were killed by Soviet secret police.

Interest in reopening the investigation into the 1940 killings has grown amid a recent Russia-Poland rapprochement.

The Soviet Union acknowledged responsibility for the killings in 1990, but a criminal investigation was ended in 2004 after officials said the killings were not genocide.

President Dmitry Medvedev this month turned over scores of volumes from the investigation to his Polish counterpart.

Russian news agencies say chief military prosecutor Sergei Fridinsky said Monday reopening the investigation was legally impossible because of the length of time that had passed.