France and Germany have asked the United States to come clean over reports that its top intelligence services have been spying on key European Union offices.
A report in Germany's Der Spiegel magazine said European Union offices in the US and Europe had been bugged by the National Security Agency (NSA).
The magazine claimed that other 'targets' included the French, Italian and Greek embassies in the US.
According to the BBC, NSA whistleblower Edward Snowden is said to be the source of the leaks.
French Foreign Minister Laurent Fabius said that if the allegations carried by the magazine were confirmed, such activities by the US would be 'totally unacceptable'.
Germany's Justice Minister Sabine Leutheusser-Schnarrenberger said the alleged US behaviour was reminiscent of the Cold War.
He added that it is beyond comprehension that the United States saw Europeans as its enemies.
European Parliament President, Martin Schulz, said he was deeply worried and shocked by the allegations, adding that such spying could have a severe impact on ties between the EU and the US, the report said.
The US government has so far made no public comments on the allegations.
