The United States National Security Agency spied on French presidents Jacques Chirac, Nicolas Sarkozy and Francois Hollande, WikiLeaks said in a press statement published on Tuesday, citing top secret intelligence reports and technical documents.
The revelations were first reported in French daily Liberation and on news website Mediapart, which said the NSA spied on the presidents during a period of at least 2006 until May 2012, the month Hollande took over from Sarkozy.
WikiLeaks said the documents derived from directly targeted NSA surveillance of the communications of Hollande (2012-present), Sarkozy (2007-2012) and Chirac (1995-2007), as well as French cabinet ministers and the French ambassador to the U.S.
According to the documents, Sarkozy is said to have considered restarting Israeli-Palestinian peace talks without U.S. involvement and Hollande feared a Greek euro zone exit back in 2012.
These latest revelations regarding spying among allied Western countries come after it emerged that the NSA had spied on Germany and Germany's own BND intelligence agency had cooperated with the NSA to spy on officials and companies elsewhere in Europe.
"The French people have a right to know that their elected government is subject to hostile surveillance from a supposed ally," WikiLeaks founder Julian Assange said in the statement, adding that more "important revelations" would soon follow.
The documents include summaries of conversations between French government officials on the global financial crisis, the future of the European Union, the relationship between Hollande's administration and Merkel's government, French efforts to determine the make-up of the executive staff of the United Nations, and a dispute between the French and U.S. governments over U.S. spying on France.
The documents also contained the cell phone numbers of numerous officials in the Elysee presidential palace including the direct cell phone of the president, WikiLeaks said.
Last week, WikiLeaks published more than 60,000 diplomatic cables from Saudi Arabia and said on its website it would release half a million more in the coming weeks.
Former NSA employee Edward Snowden created an uproar in Germany after he revealed that Washington had carried out large-scale electronic espionage in Germany and claimed the NSA had bugged Merkel's phone.
"While the German disclosures focused on the isolated fact that senior officials were targeted by U.S. intelligence, WikiLeaks' publication today provides much greater insight into U.S. spying on its allies," WikiLeaks said.
This includes "the actual content of intelligence products deriving from the intercepts, showing how the U.S. spies on the phone calls of French leaders and ministers for political, economic and diplomatic intelligence".
WikiLeaks said NSA intercepts showed that French President Francois Hollande called a secret meeting of his cabinet about the potential consequences of a Greek exit from the euro zone as early as May 2012.
It also said the Socialist Hollande, who at that point had been in power a few days, had been disappointed by a first meeting as president with conservative German Chancellor Angela Merkel and requested talks with leaders of the Social Democratic Party, her centre-left junior coalition partner.
"Hollande stressed that the meeting would be secret," WikiLeaks quoted an NSA intercept from May 22, 2012 as saying of talks he requested with "appropriate ministers" in his cabinet to discuss possible fall-out on France's economy and banks if Greece exited the euro zone.
In another intercept dated June 10, 2011, Sarkozy is said to have considered restarting Israeli-Palestinian peace talks without U.S. involvement.
An earlier one from 2008 has Sarkozy, widely considered in France to be pro-American, being critical of the U.S. government's handling of the financial crisis.
"The president blamed many of the current economic problems on mistakes made by the U.S. government, but believes that Washington is now heeding some of his advice," it said.
The French president's office was not immediately reachable for comment.
The French foreign ministry declined to comment on the WikiLeaks statement.
The U.S. State Department also declined to comment.
Hollande's office said on Tuesday the president plans to meet with his defence committee on Wednesday to discuss the WikiLeaks statement.
Michele Alliot-Marie, former defence and foreign affairs minister under Chirac and Sarkozy, told France's iTele TV channel that France had long known that the U.S. had the technical means to try to intercept conversations.
"We re not naive, the conversations that took place between the defence ministry and the president did not happen on the telephone," she said. "That being said, it does raise the problem of the relationship of trust between allies."