(This story has been updated below to reflect yet another development from the Guardian)

It can generally be assumed that Russia and the U.S. are spying on each other at all times. Spies get busted on each side with some regularity. But the latest leak from Edward Snowden shows the National Security Agency once snooped former President Dmitry Medvedev's meta-data during a summit of world leaders. (Update: turns out the British used the summit to snoop, too). The Guardian reports the NSA office in Menwith Hill tracked Medvedev's communication signals back to the Russian embassy during the G20 summit in London in 2009, according to documents leaked by former government contractor Edward Snowden. The report doesn't reveal much beyond "a change in the way Russian leadership signals have been normally transmitted." The reports major details, per the Guardian

The report says: "This is an analysis of signal activity in support of President Dmitry Medvedev's visit to London. The report details a change in the way Russian leadership signals have been normally transmitted. The signal activity was found to be emanating from the Russian embassy in London and the communications are believed to be in support of the Russian president."

But this is easily the highest profile snooping revealed by Snowden so far. While his other leaks have revealed wider operations on a very macro spying level, the Medvedev reveal shows very specific targeting of a top government official from one of the country's most uneasy allies. 

Russia and the U.S. spy on each other all the time. Russia recently expelled an American they said was a CIA spy who wore a funny wig. And who can forget the ring of Russian spies busted in the U.S. a few years ago who were allegedly building a network of spy children? But this reveal ahead of the scheduled G8 meetings that Obama and current Russian president Vladimir Putin will be attending my make things a little awkward. There's also that (disputed) matter of the stolen Super Bowl ring setting the table for a very strange conversation between the two world leaders. 

UPDATE: But wait, there's more. British intelligence officials also spied during the 2009 G20 summit, by, among other things, essentially tricking foreign diplomats into using rigged internet cafes, according to the Guardian

"The same document also refers to GCHQ, MI6 and others setting up internet cafes which "were able to extract key logging info, providing creds for delegates, meaning we have sustained intelligence options against them even after conference has finished". This appears to be a reference to acquiring delegates' online login details." 

The information was also provided by Snowden, of course. Their story alleges that the program was sanctioned by then Prime Minister Gordon Brown's administration at some senior level. The British, according to the Guardian, also monitored the email and phone messages of delegates, provided analysts with live updates on phone calls at the summit, specifically targeted the Turkish finance minister (with up to 15 other targets), and were kept updated on the NSA's attempt to keep tabs on the Russians. 

The G8 summit opens hours from now, in Northern Ireland. This should be interesting.