Francoise Hollande has said that France "will not tolerate" acts that threaten its security, following the emergence of leaked documents that purportedly show the US spied on the French president and his two immediate predecessors.

The documents, which were published last night by Wikileaks and two French newspapers, allegedly reveal the private conversations and deliberations of Hollande as well as former French presidents Nicolas Sarkozy and Jacques Chirac.

In a statement, the White House said that it was not presently spying on the French president, but did not address whether the National Security Agency had spied on him in the past.

"We do not conduct any foreign intelligence surveillance activities unless there is a specific and validated national security purpose," said Ned Price, White House National Security Council spokesman. "This applies to ordinary citizens and world leaders alike."

A statement from the French president said that the United States must respect its promise not to spy on French leaders, the BBC reports.

The documents claim to reveal private correspondence from Hollande in which the French president said that German Chancellor Angela Merkel was "fixated" on fiscal discipline and that he planned to go behind her back to talk to German opposition leaders soon after he was elected in 2012.

According to a summary of the correspondence, Hollande also began drawing up contingency plans in the event of a Greek exit from the EU in May 2012, when French officials did not publically acknowledge that Greece leaving the union was a possibility.

"The French president seems worried that if word were to get out that Paris is seriously considering the possibility of a Greek exit, it would deepen the crisis," the document reads.

The allegations contained in the documents are "likely to worsen simmering trans-Atlantic tensions over surveillance", the Wall Street Journal says.

Leaks from whistle-blower Edward Snowden in 2013 showed that the NSA tapped the mobile phone of allies including Angela Merkel.

The US said that it could not confirm the veracity of the latest reports.