German Chancellor Angela Merkel said Monday that if reports that a German intelligence employee spied for the United States are proven true, it would be a "clear contradiction" of trust between the allies.
Speaking at a news conference in China, Merkel made her first public comments on the arrest last week of a 31-year-old man suspected of spying for foreign intelligence services.
German prosecutors say the man is suspected of handing over 218 documents between 2012 and 2014. German media, without naming sources, have reported he was an employee of Germany's foreign intelligence service who says he sold his services to the U.S.
"If the allegations are true, it would be for me a clear contradiction as to what I consider to be trusting cooperation between agencies and partners," Merkel said at a news conference in Beijing with the Chinese premier.
Germany has been stepping up pressure on the United States to clarify the situation.
The White House offered no public comment, and a U.S. official said the matter did not come up during a phone call Thursday between President Barack Obama and Merkel. The phone call was scheduled beforehand to discuss other matters and Obama was not aware of the spying allegations at the time, according to the official, who insisted on anonymity because they were not authorized to publicly discuss the private call.
The spying report threatens to strain German-U.S. relations again after earlier reports that the National Security Agency spied on Germans, including on Merkel's cellphone.
The German newspaper Bild reported Monday that German Interior Minister Thomas de Maiziere wants to include the U.S. among future German spy targets in response to the case.
German Foreign Minister Frank-Walter Steinmeier said if the allegations of U.S. involvement were true, the case could change the routine for the two countries in unspecified ways.
"Should the suspicions be confirmed that American intelligence agencies were involved, then that's also a political matter where one can't just go back to the daily routine," Steinmeier said during a visit to Mongolia, according to his office.
"We will work hard to answer the outstanding questions and then decide how to react," he said. "I hope that the U.S. can contribute to resolving this matter as quickly as possible."
Deputy German government spokeswoman Christiane Wirtz told reporters in Berlin that the U.S. one of Germany's most important partners. "But that doesn't mean one has to accept without criticism whatever these partners do," she said. She stressed that any consequences would wait until the investigation is concluded.
In Berlin, former U.S. Secretary of State Hillary Rodham Clinton said in an interview with Der Spiegel, posted online Monday, that the United States would never sign a commitment with any other nation not to spy on them.
"The U.S. will never sign a no-spy agreement (as demanded by Germany) with any other countries, not with you, not with Britain or Canada," Clinton was quoted as saying. "But that doesn't mean that the two countries and their intelligence agencies shouldn't clarify what's appropriate and what isn't."