Timothy Naftali, a University of Virginia historian who has looked through the newly released documents, said yesterday they showed that West German intelligence had told the CIA that Eichmann was living in Argentina under the pseudonym Clemens two years before he was abducted by the Israelis - but the Americans did not want him captured because they feared what he might say that could compromise Hans Globke, who supported America's anti-communist goals in Europe.

Globke served as national security adviser in the postwar Bonn government of Konrad Adenauer, but had worked in the Jewish affairs department of the Nazi regime, and helped write laws excluding Jews from Germany society. "The CIA, which worked closely with Globke, assisted the West Germans in protecting him from Eichmann," Mr Naftali said.

The alias the Germans provided may not have been exact. When Eichmann was seized in May 1960, he was living under the name Klement. Israeli agents smuggled him to Israel, where he was tried and convicted for his role in the Holocaust. He was hanged in 1962. The case is one of several examples of compromises and deals the CIA made with Nazis after the war in the interests of competing with the Soviet Union for influence in Europe. Those post-war dealings with Nazis are the subject of 27,000 newly declassified documents, one of the biggest declassification projects in CIA history.