France's CNIL agency said today that European data protection agencies "consider they should evaluate the exact impact of the PRISM programme on the privacy and data of European citizens," and have written to the European Commission for its help to get information from the United States.
Revelations about PRISM and other programmes by the US National Security Agency (NSA) to capture and store personal information gleaned from emails, phone calls and web searches have sparked outrage in Europe, especially after tech giants such as Google and Facebook were implicated.
In a letter to European Commission Vice President Viviane Reding, the agencies said the "collection of and access by the American intelligence community to data on non-US persons are of great concern to the international data protection community."
Despite some clarifications from Washington, "many questions as to the consequences of these intelligence programmes remain," it said.
It said the agencies had a duty to "assess independently to what extent the protection provided by EU data protection legislation is at risk and possibly breached" by the US intelligence-gathering programme.
European sources have said governments' anger over the data surveillance is genuine, following reports of widespread spying on Washington's European allies.
Snowden, a 30-year-old former NSA contractor, received asylum in Russia on August 1, after spending more than five weeks stranded in a Moscow airport avoiding extradition to the United States.
He is wanted by Washington on espionage charges linked to his media disclosures about the secret details of the US surveillance programmes.