Another day, another revelation that the U.S. undertook a massive spying operation against one of its allies. According to a report in Spanish paper El Mundo, the NSA monitored more than 60 million phone calls in Spain over a 30-day period last year.

The report, written by Glenn Greenwald and based off a classified document provided by Edward Snowden, claims that the U.S spied on the phone calls in December 2012, monitoring the calls' numbers and duration but not their content. The system used by the NSA was also capable of accessing emails and texts, according to the report. Spain summoned the U.S. ambassador on Monday to discuss the allegations.

The report is similar to one published last week in French paper Le Monde, which claimed the U.S. recorded 70 million phone calls between civilians in France during a month-long stretch in December 2012. That report prompted a sharp rebuke from France, who also summoned the U.S. ambassador to account for his country's actions.

The week would only get worse, though, for the NSA and U.S. as reports would surface that the U.S. spied on German Chancellor Angela Merkel's cellphone since 2002 as well as on the leaders of at least 34 other countries. This is on top of prior revelations that the U.S. spied on leaders from Mexico, Britain, Brazil, and Colombia.

On Friday, Spanish Prime Minister Mariano Rajoy resisted joining France, Germany and 28 other EU members in seeking new spying regulations for the U.S.

"We'll see once we have more information if we decide to join with what France and Germany have done," Rajoy said at a news conference, according to Reuters.

[Image of Spanish Prime Minister Mariano Rajoy via AP]