German parliamentary investigators plan to question executives of telecommunications operators about reports that U.S. and U.K. intelligence gained direct access to networks of companies including Deutsche Telekom AG.

Managers of network providers since 2001 will be asked to testify because the reported acts, if confirmed, would constitute statutory offenses, said Christian Flisek, a Social Democratic lawmaker who sits on the parliamentary investigative committee in the lower house. Roderich Kiesewetter, a committee member from Chancellor Angela Merkel's Christian Democrats, said the reports have to be taken "very seriously."

The U.S. National Security Agency and its U.K. counterpart GCHQ targeted German providers as part of an effort to peer into computers and mobile devices all over the world, Der Spiegel reported Sept. 13, citing documents provided by Edward Snowden. Both Deutsche Telekom and regional provider NetCologne said they hadn't found any evidence that their networks were manipulated.

"If this turns out to be true, then this is certainly a new dimension," lawmaker Konstantin von Notz said in an interview today. "It shows that Merkel's foundational principle, that foreign security services have to conform to German law on German soil, doesn't work at all. We would be naive to think that German counterintelligence didn't know this sort of thing was going."

The agencies conducted an NSA operation called Treasure Map, which sought close to real-time access to individual routers as well as computers, smartphones and tablets connected to the Internet, Spiegel reported. The New York Times reported the existence of Treasure Map last year.