ROME (Reuters) - Italy’s foreign ministry summoned the U.S. ambassador on Tuesday after media reports that American intelligence services tapped the telephones of former Prime Minister Silvio Berlusconi and his aides in 2011.

Forza Italia party (PDL) leader Silvio Berlusconi speaks during a Northern League rally in Bologna, central Italy, November 8, 2015. REUTERS/Stefano Rellandini

Newspaper La Repubblica reported the U.S. National Security Agency (NSA) spied on the billionaire, four-time prime minister five years ago when his government was under pressure at the height of the euro zone debt crisis.

La Repubblica said whistleblowing site WikiLeaks showed the 79-year-old media tycoon and head of Italy’s main center-right party had been in the NSA’s crosshairs between 2008 and 2011.

Ambassador John Phillips met the director general of the foreign ministry, Michele Valensise, in the afternoon. Afterwards the ministry issued a statement saying that Italy had called for “specific clarifications about what emerged in relation to the events of 2011”.

Phillips “assured us that he will immediately refer the question to his superiors,” the ministry said. During the meeting, Phillips also pointed out that President Barack Obama banned eavesdropping on the leaders of close friends and allies of the United States in 2014, the statement said.

Obama made that decision in part to smooth over frayed relations between the United States and Germany after reports surfaced in 2013 that the NSA had monitored the cellphone of German Chancellor Angela Merkel.

Though Berlusconi’s influence has waned since he left government, he is still a prominent figure and leads Forza Italia, the second-largest party on the fragmented right wing of Italian politics.

Jewels in the crown of his business empire include TV company Mediaset and a majority stake in football team AC Milan.

Germany’s federal prosecutor opened an investigation into the alleged tapping of Merkel’s mobile phone by the NSA but closed it after a year in June 2015, saying there was a lack of evidence that would stand up in court.

Staunch Berlusconi ally and Forza Italia member Renato Brunetta said there had been a “conspiracy” to bring down Berlusconi, and warned current Prime Minister Matteo Renzi not to take the allegations too calmly.

“Let’s not forget how the ratings agencies downgraded Italy for no reason other than to push Berlusconi out,” Brunetta said on Twitter. In the past, Berlusconi has repeatedly accused European Union officials of a “plot” to force him out of government. Berlusconi resigned in November 2011 and was replaced by former European Commissioner Mario Monti.

A book by former U.S. Treasury Secretary Tim Geithner released in Italy in 2014 suggested EU officials had approached the United States with a project to force Berlusconi to step down.