Paris, Jul 1 (IANS): France has called on the US to explain spying allegation on the European Union (EU) offices in Washington, Brussels and the UN.

"We are waiting the US authorities to answer as soon as possible the legitimate questions raised by press report," reported Xinhua citing French Foreign Affairs Minister Laurent Fabius in a statement Sunday. "If these allegations would be confirmed, they would be totally unacceptable."

The US National Security Agency had tapped EU offices and gained access to EU internal computer networks, the Der Spiegel magazine reported Saturday, while stating that its report was based on confidential documents, some of which it had managed to consult via fugitive ex-CIA analyst Edward Snowden.

The US did not react immediately.

Representing almost the half of the world's total output, the US and the European Union started talks in June to forge a free trade accord expected to spur growth and create jobs on both sides of the Atlantic.