PARIS- U.S. President Barack Obama reaffirmed in a phone call with his French counterpart Francois Hollande on Wednesday Washington's commitment to end spying practices deemed "unacceptable" by its allies.

The presidents' conversation, announced by Hollande's office, came after transparency lobby group WikiLeaks revealed on Tuesday that U.S. National Security Agency (NSA) had spied on the last three French presidents.

The latest revelations of espionage among Western allies came after it emerged that the U.S. National Security Agency (NSA) had spied on Germany and that Germany's own BND intelligence agency had cooperated with the NSA to spy on officials and companies elsewhere in Europe.

"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 U.S. ambassador was summoned to the foreign ministry.

"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 U.S. spying on French interests had surfaced.

A senior French intelligence official will travel to the United States to discuss the matter and strengthen cooperation 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.

While Paris and Washington have good ties in general, U.N. Security Council veto-holder France fiercely maintains its independence on foreign policy and over the last two years there have been moments of friction and irritation on both sides.