The global fallout from the leaks of former National Security Agency contractor Edward Snowden escalated Wednesday after new claims of U.S. spying on Germany. German Chancellor Angela Merkel personally phoned President Obama to complain about the apparent tapping of her cellphone. The German government did not provide details, but the newspaper Der Speigel says Merkel acted following an inquiry by its reporters. In Washington, White House Press Secretary Jay Carney said the United States is not spying on Merkel, but left out whether the United States has done so in the past.

White House Press Secretary Jay Carney: “I can tell you that today President Obama and Chancellor Merkel spoke by telephone regarding the allegations that you mentioned, that the U.S. National Security Agency intercepted the communications of the German chancellor. And I can tell you that the president assured the chancellor that the United States is not monitoring and will not monitor the communications of the chancellor.”

According to a spokesperson, Merkel told Obama that U.S. spying “would be a grave breach of trust” and “must cease immediately.” As part of the continued fallout, German’s Foreign Ministry has now summoned the U.S. ambassador to Germany, John Emerson, to discuss the spying claims. The spat with Germany comes just days after it was revealed the U.S. carried out the mass surveillance of French citizens and also spied on French diplomats. Snowden’s leaks also disclosed the NSA hacked the email accounts of then-President Felipe Calderón in 2010 and of current Mexican President Enrique Peña Nieto before he was elected.