Antennas and suspected covered windows (L) are pictured on the roof of the U.S. embassy in Berlin October 27, 2013. A German newspaper said on Sunday that U.S. President Barack Obama knew his intelligence service was eavesdropping on Angela Merkel as long ago as 2010, contradicting reports that he had told the German leader he did not know. The U.S. National Security Agency (NSA) denied that Obama had been informed about the operation by the NSA chief in 2010, as reported by the German newspaper. REUTERS/Fabrizio Bensch (GERMANY - Tags: POLITICS)

MADRID (Reuters) - Spain summoned the U.S. ambassador on Monday to discuss allegations of spying on Spanish citizens that it said could break the climate of trust between the two countries if proved true.

Earlier, the Spanish newspaper El Mundo said the NSA had recently tracked over 60 million calls in Spain in the space of a month, citing a document which it said formed part of papers obtained from ex-NSA contractor Edward Snowden.

"I had been in touch with (the U.S. ambassador) before this morning's meeting...So far, we have no official indication that our country has been spied on," Spanish Foreign Minister Jose Manuel Garcia-Margallo said at a joint news conference with his Polish counterpart in Warsaw.

"As in previous occasions, we've asked the U.S. ambassador to give the government all the necessary information on an issue which, if it was to be confirmed, could break the climate of trust that has traditionally been the one between our two countries."

Madrid has also asked the United States to provide more data from the National Security Agency (NSA), the foreign ministry said in a statement issued after a meeting between Spain's Secretary of State for the European Union, Inigo Mendez de Vigo, and U.S. Ambassador to Spain James Costos.

U.S. President Barack Obama has ordered a review of U.S. surveillance programs after Snowden leaked documents that raised alarm in the United States and abroad.

"We will continue to confer with our allies, such as Spain, through our regular diplomatic channels to address the concerns that they have raised," Costos said in a statement.

Spain has so far resisted calls from Germany for the European Union's 28-member states to reach a "no-spy deal", after reports that the NSA monitored the phone of German chancellor Angela Merkel.

El Mundo reproduced a graphic on Monday which it said was an NSA document showing the agency had spied on 60.5 million phone calls in Spain between December 10, 2012 and January 8 this year.

The newspaper said it had reached a deal with Glenn Greenwald, the Brazil-based journalist who has worked with other media on information provided to him by Snowden, to get access to documents affecting Spain.

El Mundo said the telephone monitoring did not appear to track the content of calls but their duration and where they took place.

Snowden is currently living in Russia, out of reach of U.S. attempts to arrest him.

(Reporting by Sarah White, Emma Pinedo and Tracy Rucinski; Additional reporting by Marcin Goettig in Warsaw; Editing by Paul Day and Ralph Boulton)