WASHINGTON — The CIA kept quiet about the whereabouts of Nazi war criminal Adolf Eichmann in the 1950s for fear he might expose undercover anti-communist efforts in West Germany, U.S. documents released Tuesday show.

The 27,000 pages released by the National Archives are among the largest post-Second World War declassifications by the CIA. They offer a window into the shadowy world of U.S. intelligence -- and the efforts to use Nazi war criminals as spies, sometimes to detrimental effect.

The war criminals "peddled hearsay and gossip, whether to escape retribution for past crimes, or for mercenary gain, or for political agendas not necessarily compatible with American national interests,'' Robert Wolfe, an expert on German history and former archivist at the National Archives, said at a news briefing announcing the document release.

In a March 19, 1958, memo to the CIA, West German intelligence officials wrote they knew where Eichmann was hiding. Eichmann played a key role in transporting Jews to death camps during the Second World War.

"He is reported to have lived in Argentina under the alias `Clemens' since 1952,'' authorities wrote.

But neither side acted on that information because they worried what he might say about Hans Globke, a highly placed former Nazi and a chief adviser in West Germany helping the United States co-ordinate anti-communist initiatives in that country.

Two years later, when Israeli authorities captured Eichmann, the CIA put pressure on journalists to delete references to Globke.

"Entire material has been read. One obscure mention of Globke which Life omitting at our request,'' CIA Director Allen Dulles wrote in a Sept. 20, 1960, internal memorandum, after Life magazine purchased Eichmann's memoir.

Among the other findings:

• Former Nazi officers such as Heinz Felfe, who served in the "Gehlen organization'' -- the West German intelligence service which in its early years was sponsored by the U.S. army and then the CIA -- were typically hired by the Soviet Union to be double agents.
• The CIA routinely misled U.S. immigration officials in the mid-1970s about the role of CIA agent Tscherim Soobzokov and his connection to Nazi war crimes.

The documents were among the latest released under a 1999 law -- resisted by the CIA -- that called for disclosure of government records related to war crimes committed by the Nazi and Japanese governments.

"CIA has been struggling with the nettlesome problem of how to balance the public's interest in the historical record of CIA's connections to Nazis and an intelligence agency's need...to protect the identities of sources,'' said Stanley Moskowitz, a former CIA official who is now a consultant to the agency.

"The passage of time has shifted the balance,'' he said.

Material relating to Japanese war crimes are scheduled to be released later this summer.