The transfer took place on Monday in line with an agreement to open up the archive managed by the International Tracing Service (ITS) in the German town of Bad Arolsen, which maintains the world's most extensive archive regarding Nazi concentration camps.

"These documents reflect the most despicable operations of the Nazi era and constitute an essential part of our archive," ITS director Reto Meister said in a statement Tuesday.

The ITS, an arm of the International Committee of the Red Cross, helps survivors of the camps to claim pensions and compensation and assists families who want to know where their loved ones suffered.

More access for researchers

"Above all, the victims of the Holocaust, their families and researchers stand to benefit from this development," Meister said. "After a long political process, we can now give researchers and the public access to the files."

The ITS had withheld the papers from researchers until the 11-member, international commission governing the archives agreed in May to sidestep legal barriers and allow wider access in a move Jakob Kellenberger, the president of the ICRC, called "a first step" to providing broader access to the documents.

The change will allow historians to view the collections in Bad Arolsen as well as the US Holocaust Memorial Museum in Washington and the Yad Vashem Martyrs' and Heroes' Remembrance Authority in Jerusalem.

"This first transfer is the beginning of a major undertaking," Sara J. Bloomfield, director of the Washington museum, said in a statement Tuesday. "Our goal is to help survivors."

Complete data available in 2009

The two institutions received some 12 million digitized documents, about one-third of the Bad Arolsen archive. The rest of the files, most of which are written by hand and sometimes in an old German script, are scheduled to be digitized and delivered by early 2009.

All of the data will be made available to researchers and the public after all 11 ITS member states ratify the legal change. Italy, France and Greece have yet to ratify the agreement, while the United States led pressure to open the sealed archives to families and others before the last Holocaust survivors die.

The data was transferred under embargo to allow officials to begin processing the files and making technical preparations for the archive's formal opening, Meister said.

"The material received last night is complex and vast, taken from a number of camps, which is organized in complicated and varying ways," Avner Shalev, Chairman of Yad Vashem, said in a statement Tuesday. "We expect it will take a lot of resources to sift through the material and catalog it."

The documents, kept in six buildings at Bad Arolsen, a remote town in hills north of Frankfurt, are only a part of the world's scattered stock of personal data on Nazi victims. Prisoner-of-war data is kept separately by the Central Tracing Agency in Geneva, Switzerland.