American and British spying agencies were intercepting phone and internet data of foreign dignitaries attending the G20 Summit in 2009, according to The Guardian.

The paper revealed top-secret documents provided by NSA whistleblower Edward Snowden, which talked about "recent successes" in surveillance from GCHQ —Britain's NSA equivalent.

From The Guardian:

There have often been rumours of this kind of espionage at international conferences, but it is highly unusual for hard evidence to confirm it and spell out the detail.

The documents — prepared by the NSA and briefed to officials in Britain, Canada, Australia, and New Zealand — reveal some surprising details, including the eavesdropping of phone calls of Russia's then-President Dmitry Medvedev, and the monitoring of emails and calls from other attending delegates' Blackberrys. The spy agency also reportedly set up fake internet cafes to intercept emails and install software to record keystrokes.

Released on Sunday, the new documents are the latest in nearly two weeks of revelations — from the collection of millions of Verizon phone records to Snowden's claim that he had the ability to wiretap anyone in the country from his desk.

The details are sure to mark a tense opening to the G8 Summit scheduled to start Monday in Ireland, with all nations who were present at the London G20 set to attend, RT reports.