If diplomats at the U.S. Embassy in Berlin turn out to be the "culprits" who monitored German Chancellor Angela Merkel's phone, they must leave Germany, Interior Minister Hans-Peter Friedrich says, calling the incident "unacceptable."

The minister said the German government will try to clarify how the alleged spying occurred, Reuters reported.

The accusations arose after the German newsmagazine Der Spiegel gave the government evidence that the U.S. National Security Agency had monitored Merkel's mobile phone for more than 10 years.

"If we find culprits and if we can identify them, they must live with the legal consequences, and if they are diplomats, they must leave the country," Friedrich said Monday.

"I am, of course, disappointed that an intelligence service, which elsewhere co-operates closely with us in the fight against terror, thinks they have the right to monitor the chancellor. That is something we can not accept."

In addition, German officials suggested that U.S. access to a tool used to track terrorist money flows could be cut off in response to the allegations of spying. Germany pointed to a non-binding resolution last week by the European Parliament to suspend an agreement allowing U.S. access to bank transfer data.

German Justice Minister Sabine Leutheusser-Schnarrenberger said the deal, commonly known as the SWIFT agreement, should be suspended.

"It really isn't enough to be outraged," she told rbb-Inforadio. "This would be a signal that something can happen and make clear to the Americans that the [EU's] policy is changing."

The White House also rebutted suggestions from Leutheusser-Schnarrenberger that the U.S. was using the data to collect economic intelligence, and not just to combat terrorism.

More allegations of U.S. spying on Western Europe emerged Monday when Spanish newspaper El Mundo published a document it said showed the NSA listened in on more than 60 million phone calls in Spain between December 2012 and January 2013.

Spain's Foreign Ministry summoned the U.S. ambassador to Spain to give an explanation.

Senator Diane Feinstein, the chairwoman of the U.S. Senate intelligence committee, on Monday called for a "total review of all intelligence programs" amid the mounting fallout from the U.S. eavesdropping on its allies.

Feinstein said she was not told about the spying on Merkel, but that the intelligence community kept her informed on other matters, such as court orders on phone record collection.

"With respect to NSA collection of intelligence on leaders of U.S. allies — including France, Spain, Mexico and Germany — let me state unequivocally: I am totally opposed," Feinstein said Monday.