The U.K. has been secretly gathering communications data from American Internet giants with the help of fellow spooks at the U.S. National Security Agency, the Guardian newspaper reported Friday, a demonstration of the international scope of America’s top-secret espionage program.

The Guardian said it had seen documents showing how the British signals intelligence agency GCHQ has had access to America’s “PRISM” electronic eavesdropping system since at least June 2010, adding that the data had generated nearly 200 intelligence reports over the past year.

GCHQ declined to comment on the story Friday, saying only that it takes its legal obligations “very seriously.”

The Guardian said evidence for GCHQ’s involvement came from the same 41-page Powerpoint presentation cited Thursday by both that paper and The Washington Post as the basis for their reports on PRISM, a heretofore-unknown eavesdropping program used to collect emails, documents, audio, video, and other data from major Internet companies including Microsoft, Yahoo, Google, Facebook, PalTalk, AOL, Skype, YouTube, and Apple.

While PRISM is theoretically targeted at data belonging to foreigners on foreign soil, the Post said that the spies merely have to believe there’s a better than even chance that the target is foreign before scooping up its data. The paper also cited training material as saying that inadvertently spying on Americans was “nothing to worry about.”

It’s not clear whether British officials would be subject to the same restrictions with respect to their own citizens, and the traditionally close links between GCHQ and the NSA have already worried some in the U.K. who fear that British spies may be eavesdropping on their own citizens through American espionage programs.

“The U.K. government must tell us what they knew about PRISM,” said Jim Killock, who directs the London-based Open Rights Group. In a statement released earlier Friday, Killock called for an investigation into “whether the U.K. government or intelligence agencies were in any way involved with any related invasion of U.K. citizens’ privacy.”

(AP)