Germans probing the surveillance activities of the US National Security Agency have uncovered a legal loophole that allows the country's foreign intelligence agency to spy on its own citizens.

The agency, known by its German acronym BND, is normally forbidden from eavesdropping on Germans or German companies. But a former BND lawyer told parliament this week that Germans aren't protected while working abroad for foreign companies. The government confirmed that work-related calls or emails are attributed to the employer. If the employer is foreign, the BND can intercept them.