Hollande Obama
US President Barack Obama and first lady Michelle Obama welcome French President François Hollande to the White House for a State DinnerReuters

US President Barack Obama has apologised to France for the National Security Agency's eavesdropping on three presidents and reaffirmed Washington's commitment to end spying practices deemed "unacceptable" by its allies.

In a phone call with François Hollande on 23 June, "President Obama reiterated unequivocally his firm commitment ... to end the practices that may have happened in the past and that are considered unacceptable among allies," the French president's office said.

Hollande had earlier held an emergency meeting of his ministers and army commanders and the US ambassador was summoned to the foreign ministry, reported Reuters. The meeting came in the wake of Wikileaks revelations that the NSA had spied on former presidents Jacques Chirac and Nicolas Sarkozy, as well as Hollande himself.

"France will not tolerate actions that threaten its security and the protection of its interests," an earlier statement from the president's office said, adding it was not the first time allegations of US spying on French interests had surfaced.

A senior French intelligence official will travel to the United States to discuss the matter and strengthen co-operation between the two countries, Hollande's office said.

"We have to verify that this spying has finished," Stephane Le Foll, government spokesman, told reporters, adding that ministers had been told to be careful when speaking on their mobile phones.

'Let's keep this in perspective'

According to the documents released by Wikileaks and published by French daily Liberation, Sarkozy considered restarting Israeli-Palestinian peace talks without US involvement and Hollande feared a Greek eurozone exit in 2012.

Wikileaks said it would soon publish more details on the nature of U.S. spying on France.

Le Foll added: "In the face of threats that we face and given the historic ties linking us, we have to keep a perspective. We're not going to break diplomatic ties."

Claude Gueant, Sarkozy's former chief of staff and one of the reported targets of the NSA, told RTL radio: "I feel like trust has been broken."