BERLIN -- German Chancellor Angela Merkel complained to President Barack Obama on Wednesday after learning that U.S. intelligence may have targeted her mobile phone, saying that would be "a serious breach of trust" if confirmed.
For its part, the White House denied that the United States is listening in on Ms. Merkel's phone calls now. "The president assured the chancellor that the United States is not monitoring and will not monitor the communications of the chancellor," White House spokesman Jay Carney said. "The United States greatly values our close cooperation with Germany on a broad range of shared security challenges."
But Mr. Carney did not specifically say the United States had never monitored or obtained Ms. Merkel's communications.
The German government said it responded after receiving "information that the chancellor's cell phone may be monitored" by U.S. intelligence. It wouldn't elaborate, but German news magazine Der Spiegel, which has published material from NSA leaker Edward Snowden, said its research triggered the response.
Merkel spokesman Steffen Seibert said in a statement that the chancellor made clear to Mr. Obama in a phone call that "she views such practices, if the indications are confirmed, ... as completely unacceptable."
Ms. Merkel said that among close partners such as Germany and the United States, "there must not be such surveillance of a head of government's communication," Mr. Seibert said. "That would be a serious breach of trust. Such practices must be stopped immediately."
At the White House, Mr. Carney said the United States is examining Germany's concerns as part of an ongoing review of its intelligence gathering. The White House has cited that review in responding to similar spying concerns from France, Brazil and other nations.
U.S. allies knew that the Americans were spying on them, but had no idea how much. As National Security Agency spying program details have become public, citizens, activists and politicians in nations from Latin America to Europe have expressed outrage at their scope.
Ms. Merkel had previously raised concerns over electronic eavesdropping when Mr. Obama visited Germany in June, has demanded answers from the U.S. government and backed calls for greater European data protection. But Wednesday's statement was much more sharply worded and appeared to reflect frustration over the answers Washington has provided so far.
Overseas politicians are also using the threat to their citizens' privacy to drum up their poll numbers -- or distract attention from their own domestic problems. Some have even played down the matter to keep good relations with Washington.
After a Paris newspaper reported that the NSA had swept up 70.3 million French phone records in a 30-day period, the Paris government summoned the U.S. ambassador for an explanation and put the personal data protection issue on the agenda for the European Union summit that opens today.
In Germany, opposition politicians, media and privacy activists have been outraged over U.S. eavesdropping. Until now, Ms. Merkel had worked to contain damage to U.S.-German ties and refrained from negative remarks against the U.S. She has previously said her country was "dependent" on cooperation with U.S. spy agencies, crediting a U.S. tip as the reason security services foiled an Islamic terror plot in 2007 that targeted U.S. soldiers and citizens in Germany.