MOSCOW (AP) _ The Russian government has released secret documents that show dozens of American fliers were shot down and killed or captured during spy missions over the former Soviet Union, military officials said Thursday.

Most of the downings, as well as the spy flights themselves, were kept secret by both sides.

''Our American colleagues have found lots of new information, including data and names of Americans who were held rather than missing,'' said Viktor Mukhin, the head of the Defense Ministry's historical archive section.

The U.S.-Russian commission on POWs and MIAs called the information interesting but said it probably would not lead to the discovery of any living American prisoners on former Soviet territory, said spokesman Sergei Osipov.

The newly declassified documents were given to commission investigators last week, said Osipov, an aide to commission co-chairman Gen. Dmitri Volkogonov.

The documents also contained information on U.S. servicemen who disappeared during the Korean War, as well as on Soviet pilots shot down over Korea during that war.

As for the downed spy planes, Osipov said the documents concerned 10 cases the commission is investigating in which U.S. aircraft were shot down over former Soviet territory during the Cold War.

''Taking into account that a crew usually consisted of seven to 15 people, we can say that dozens of people were killed,'' Osipov said in an interview.

The United States conducted hundreds of such flights during the Cold War.

''Among these documents are reports of (Soviet) pilots who followed the planes and shot them down,'' Mukhin told The Associated Press. He said several dozen American planes were destroyed.

Mukhin gave few details about the documents concerning Americans and the Korean War, saying the bulk of these files dealt with Soviet-North Korean relations and Soviet planes shot down over Korea.

Osipov said the files contained some information about Americans, but he gave no details.

Last month, the vice-chairman of the U.S. Senate Committee on POW and MIA Affairs, Sen. Bob Smith, R-N.H., told a Senate hearing that Americans missing in action in the Korean War could still be alive in Russia.

Smith released a document accusing North Korea of not returning a large number of American servicemen at the end of the war. Some of the men - probably fewer than 50 - were sent to China and the Soviet Union, researchers have said.

The fate of about 3,400 American servicemen in the Korean War remains unknown, said Paul Cole, a Rand Corp. researcher under contract to the U.S. Defense Department.

Russian defense officials said Thursday they know of 113,681 foreign soldiers buried in Russia since World War II, most in the 997 cemeteries in former prison camps.

But they said searchers were looking for others, who may have died elsewhere, such as in the tundra or swamps of Siberia.

The officials also said they plan to build war memorials for all foreign soldiers who died on Russian territory.