High-ranking representatives of German security services and the chancellery will meet U.S. intelligence officials Wednesday in Washington to seek clarifications of widespread spying allegations including U.S. intelligence's tapping of Chancellor Angela Merkel's phone.

Merkel' s foreign policy advisor Christoph Heusgen and German intelligence coordinator Gunter Heiss will meet U.S. National Security Adviser Susan Rice, Director of National Intelligence James Clapper, and President Barack Obama' s counterterrorism adviser Lisa Monaco.

The two sides will discuss the scale of the alleged U.S. spying program in Europe and tapping of Merkel's phone communications.

The German government has voiced its anger at possible U.S. intelligence's tapping of Merkel's phone, saying it would be "a serious breach of trust" if confirmed.

However, U.S. National Security Agency Director General Keith Alexander on Tuesday told lawmakers that the recent media reports about the agency's spying on European allies are "completely false."

U.S. allies in Europe have been in an uproar over the media reports that U.S. intelligence agencies have monitored the communications of Merkel and tens of millions of phone calls in France and Spain.