Bad Arolsen, Germany - The world's biggest archive of original Holocaust documents is already revealing close-up detail about the genocide that was previously unknown, a top US historian, Paul Shapiro, said in Germany on Thursday.

Historians won access in April to the storehouse, maintained for decades by Red Cross officials at Bad Arolsen in provincial Germany. Images of the documents are gradually being sent to Washington and Jerusalem.

Shapiro, who is chief historian at the US National Holocaust Museum in Washington DC, said in Bad Arolsen, "Nobody can even begin to imagine the scope of the documents stored here."

It was clear that the evidence in the papers would trigger new debate "and alter our picture of the Holocaust," he said.

The information would reinforce past verdicts, but also offer new details of German officials' mentality and of life in concentration camps, said Shapiro, who is in charge of the first party of scholars to begin detailed research in the papers.

Several buildings maintained by the Red Cross International Tracing Service (ITS) at Bad Arolsen contain more than 50 million pages of data covering the fates of 17.5 million non-Germans.

They were caught up in the War or its aftermath as camp inmates, forced labourers and displaced persons, with many being killed.

Shapiro's museum led an international campaign to end the secrecy of the archives, which are based on captured Nazi documents. Previously only relatives or survivors were allowed to see an individual's records.

Another US historian, Jessica Hughes, illustrated the possible revelations.

"I am studying forced prostitution in the concentration camps and I've found material here that gives a completely new, much more precise picture of it," she said.

"These files are also fascinatingly revealing about how the Holocaust was seen after the war and about the reparations," said Jean-Paul Dreyfus, a French historian now based in Manchester, Britain. (dpa)