One month ago, the US was lauding France for being its oldest ally, but now the relationship is under intense pressure.

It is rather amusing that the French are supposedly so morally outraged, the French intelligence services have long engaged in spying on foreign countries .... The French are only behind the Chinese as being rather notorious in the amount of industrial espionage carried on by the French government.

Gene Arthur Coyle, a former CIA agent

Reports in France's Le Monde newspaper accuse the US of spying on millions of French citizens - a move president Francoise Hollande said was "unacceptable between friends and allies", demanding an explanation.

US President Barack Obama called his French counterpart on Monday, saying the US was reviewing how it gathers intelligence.

US Secretary of State of John Kerry, who arrived in Paris the same day, said Washington's goal was to find the right balance between protecting the security and the privacy of their citizens.

These are the latest in a series of accusations against the National Security Agency (NSA).

Last month, news broke that the NSA had intercepted the communications of Brazilian President Dilma Rousseff, who called it "an unacceptable violation of sovereignty".

It was also recently revealed the NSA was spying on Mexico's former President Felipe Calderon. It gave the US access to his email account and turned his office into "a lucrative source of information."

The news that Germany was the most spied on European country was met with a massive outcry. European officials also became a target - it was revealed the NSA has spied on the European Union's offices in Brussels and Washington DC.

Some of the least talked about NSA leaks relate to allegations of US spying on foreign businesses. The US Department of Defence has said it "does not engage in economic espionage" of any kind. But slides from an NSA presentation from 2012 specifically mention an economic motive for spying, along with diplomatic and political reasons.

It has been reported that spying on the Mexican government provided US politicians with reports that helped them plan international investments. Among the international businesses the NSA allegedly spied on are the Chinese technology firm Huawei, and Brazil's state-run oil company Petrobras, which is known to have discovered some of the world's biggest offshore oil reserves in recent years.

So why would the US spy on its allies? Is France's anger justified or is it being blown out of proportion? And what are the  possible diplomatic or economic consequences of the NSA spying scandal?

Inside Story, with presenter Mike Hanna, speaks to guests: Anne Elisabeth Moutet, a columnist for the Sunday Telegraph; Jesselyn Radack, the national security and human rights director of the Government Accountability Project, a whistleblower organisation; and Gene Arthur Coyle, a professor at Indiana University and a former CIA agent.

"The fact that other countries spy on their own people or spy on each other does not address the fact that the US is engaged in massive, bulk collection to the tune of 70.3 million telecommunications a month in France of perfectly innocent people. That has nothing to do with protecting the United States, and has nothing to do with really gathering any kind of meaningful intelligence on France. It is an overreach ... and I think the other countries are justifiably outraged .... As one of our founders said: Those who choose between liberty and security deserve neither."

Jesselyn Radack, the Government Accountability Project

Source: Al Jazeera