Politicians and officials who participated in the 2009 G20 summit had their phone and computer activity monitored by the British government, which was hosting the event, according to The Guardian newspaper.

The revelation is the latest disclosure from Edward Snowden, a former government contractor, who earlier this month shared classified information detailing the U.S. National Security Agency's monitoring of phone and Internet data.

The report comes ahead of the G8 summit in Northern Ireland, where talks over Syria and a U.S.-European Union trade accord threaten to be overshadowed by the growing controversy over secret surveillance. 

According to The Guardian, during the 2009 meeting of the Group of Twenty Finance Ministers and Central Bank Governors in London, the computer and phone activity of foreign officials was monitored by the Government Communications Headquarters (GCHQ), the British counterpart to the National Security Agency.

In some cases the foreign officials were encouraged to use fake Internet cafes set up so that their correspondence could be secretly monitored. 

The GCHQ also monitored the phone calls and emails from delegates’ BlackBerrys. Forty-five analysts were tasked with providing a "live round-the-clock summary" of the monitored communications, The Guardian reported. 

The secret monitoring was meant to give British officials an advantage in the G20 meetings, and the documents suggest the surveillance may have been sanctioned by then-Prime Minister Gordon Brown. 

The documents leaked by Snowden suggest the NSA also attempted to secretly monitor then-Russian President Dmitry Medvedev's phone calls to Moscow.