Germany, Israel and the United States have signed an agreement allowing researchers access for the first time to millions of World War II Nazi German files describing how the Holocaust was carried out.

The archives contain an estimated 50 million documents on 17 million individuals. They are expected to shed new light on the Holocaust, in which six million Jews across Europe were murdered.

The accord was reached by the 11-nation governing body of the International Tracing Service - an arm of the International Red Cross founded after the war to trace missing persons.

Agreement was required from all 11 nations to change access rules. Israel, Britain, France and Greece joined the United States, Germany, Luxembourg and Italy in signing the protocol Wednesday.

Poland, Belgium and the Netherlands require further parliamentary approval, and are expected to sign later this year.

Access to the archive - housed in the western German town of Bad Arolsen - had been limited to Holocaust victims and researchers with written permission from survivors or their families. However, aging survivors who backed the change voiced fears that histories of their loved ones could be lost, unless access for researchers is broadened.

Some information for this report was provided by AFP, AP and Reuters.