According to media reports, Germany's public prosecutor has launched an investigation into three spies from Switzerland's all-seeing Federal Intelligence Service (NDB). Citing trusted sources, late Sunday Süddeutsche Zeitung and public broadcasters reported that the federal prosecutor's office had quietly begun looking into accusations that the NDB had committed espionage within Germany at the beginning of August.

The prosecutor's office has yet to respond to requests for comment on the investigation into an allied intelligence agency in the service of a neighboring nation. The names of the three suspected Swiss spies have yet to be released.

The case bears similarities to that of Daniel M, a Swiss private investigator who was arrested in Frankfurt while apparently working on orders from high up in the NDB when he procured personal information about German tax authorities. Daniel M - whose full name has not been released in accordance with German laws to protect the identities of suspects before their trials have concluded - has been in custody since spring while the investigation continues.

Switzerland is a well-known refuge for tax dodgers, which has led to a long-running fiscal dispute with Germany. The investigation into Daniel M uncovered a possible additional spy in the offices of state tax authorities in North Rhine-Westphalia.

Watch video 01:01 Tax-dodging Swiss bank closes

mkg/kms (AFP, dpa)