French President Francois Hollande condemned US spying on French citizens in a call with President Barack Obama on Monday, as a row escalated over US eavesdropping on millions of French phone calls.
Hollande's office said in a statement that he had expressed "deep disapproval of these practices, which are unacceptable between friends and allies because they infringe on the privacy of French citizens."
Hollande "asked that all explanations be provided, as well as all information that could be at the disposal of former NSA consultant Edward Snowden."
The statement said the two leaders had agreed "to work together to determine the facts and the exact scope of surveillance activities" revealed by French newspaper Le Monde.
The two stressed that surveillance operations should be put into a "bilateral framework" and agreed that US and French intelligence agencies would "work together to this effect," the statement said.