Sweden over the weekend revealed that in the mid 1990s, the Swedish security police SAPO uncovered and identified a network of some 50 Swedish spies that worked for East Germany's notorious secret police during the Cold War.

Cases were launched against a number of Stasi spies on the list, but the charges were dropped because too much time had passed, a report on the BBC News Web site said.

“The Stasi was interested in Sweden because it was neutral but had some co-operation with NATO and they wanted to find out its real position,” investigative journalist Bjorn Cederberg, the author of "Comrade Spy," a book about the Stasi espionage network that had first mentioned the 50 Swedish spies, told the site.

The Berliner Zeitung newspaper said in its weekend edition that Sweden was used as a transit country to smuggle into East Germany Western arms and high technology.

The revelations coincide with the 46th anniversary of the construction of the Berlin Wall and a discussion over the existence of government and Stasi shoot-to-kill orders that led to the killings of more than 1,000 people who tried to flee the Communist country.