We will handle it in such a way that there are no indiscretions

German Chancellor Gerhard Schroeder

German Government spokesman Uwe Karsten-Heye said the first of a planned series of CD-ROM discs containing the files had arrived last Friday.

But he stressed that the extent of the new information was still unclear.

"First we have to find out exactly what is in there," he told a news conference, adding that the delivery of up to 1,000 further CD-ROMs was planned over the next 18 months.

Interior Ministry officials and the Gauck Commission, which administers Stasi records, will now examine the data, before determining how much of it should be made public.

Chancellor Gerhard Schroeder said the information would be treated confidentially.

Prosecutions unlikely

The Stasi, or Ministry for State Security (Staatsicherheit), was responsible for both domestic political surveillance and foreign espionage.

It extensively penetrated West Germany's governing circles and military and intelligence services.

On public display: Bags of documents shredded by the Stasi

Some historians say the Stasi ran up to 20,000 agents in West Germany, but there have been only 250 prosecutions since unification in 1990.

A spokeswoman for the Federal Prosecutor said further prosecutions were unlikely due to a 10-year statute of limitations on spying.

Germany has already decoded large quantities of Stasi material containing the codenames of spies. The new files are believed to reveal the identities behind the aliases.

The handover is likely to stoke a fierce debate about whether Stasi information should be used to investigate a slush fund scandal surrounding former Chancellor Helmut Kohl.

He has insisted that records of phone conversations with aides that were tapped by East German spies while he was chancellor should not be used either in the criminal investigation or a parliamentary inquiry against him.