Politicians of every stripe in Germany expressed outrage on Saturday to allegations that a member of Germany's foreign intelligence agency, the BND, had operated as a double agent. The 31-year-old man was arrested on Wednesday.

The agent was reportedly suspected of selling information to the United States National Security Agency (NSA) directly concerning the German parliamentary comittee investigating NSA activity, according to a joint report from public regional broadcasters WDR and NDR, combined with the daily Süddeutsche Zeitung newspaper.

"This case must now be explained without any gaps," said the interior affairs spokesman for Chancellor Merkel's Christian Democrat alliance, Bavarian politician Stephan Mayer, in Saturday's edition of mass-circulation newspaper Bild. "If it should prove to be true that the BND employee worked for years as a double agent directed by the US embassy, that would be an enormous breach of trust in the Transatlantic relationship."

"In an already fragile situation, this espionage case would present another severe test for German-American ties," Mayer also told Bild.

The NSA's reach reportedly stretches to the committee in Berlin investigating it

The German Foreign Ministry summoned US Ambassador John Emerson on Friday evening, requesting that he "contribute to a speedy clarification" of the situation.

'Attack on the German parliament'

The Social Democrats' representative within the cross-party NSA inquiry, Christian Flisek, said in an interview with NDR Info that if the media allegations proved to be true, the espionage would constitute "an attack on the German parliament."

The Bild paper reported that the suspect had handed a total of 218 scanned documents over to the NSA in return for payment of 25,000 euros ($34,000), making the trades in the course of three meetings in neighboring Austria.

The opposition Greens' inquiry member, Konstantin von Notz, told the Saturday edition of the Ruhr Nachrichten newspaper that it was unacceptable "if the NSA inquiry, which should provide clarification on the surveillance of millions of Germans, is itself under surveillance."

Last year's allegations of widespread global NSA espionage triggered by Edward Snowden reverberated particularly in Germany, a country with relatively recent memories of oppressive secret services, both in former Communist East Germany and under Adolf Hitler. Last October, Der Spiegel news magazine reported that the NSA had tapped Merkel's cell phone. In March of 2014, the German parliamentary inquiry began its work.

Former US Secretary of State Hillary Clinton told the Guardian newspaper on Friday that she believed Snowden, currently on a temporary asylum deal in Moscow, should return to the US to defend himself if he stood by his decision to go public with his information.

Clinton is touring Europe to promote her new book "Hard Choices", which is seen by many as a precursor to a possible Democrat presidential bid for 2016. She will appear in an interview with DW TV's Brent Goff this week; Goff said on Twitter that the latest "spy shocker" could elicit some "hard questions."

msh/se (AFP, dpa)