US President Barack Obama has cancelled a planned G20 meeting with Russian President Vladimir Putin, according to senior administration officials.
The decision to cancel the president's trip to St. Petersburg is in response to growing US frustration at the Russian government's continued refusal to hand over Edward Snowden over charges of leaking classified information.
Only yesterday, Obama expressed his "disappointment" over the Russian decision to grant Snowden asylum for one year.
The former intelligence contractor has admitted leaking information about US surveillance programmes to the media.
Edward Snowden is a former intelligence worker for both the National Security Agency (NSA) and the CIA. In June, he leaked classified information to the Guardian and Washington Post pertaining to alleged NSA eavesdropping on telephone calls and emails of private citizens.
After fleeing his home in Hawaii, Snowden arrived in Moscow airport, via Hong Kong. After staying in the airport for more than a month, on 1st August the Russian government decided to grant him political asylum, much to the fury of the US government, which challenged that Snowden's actions had severely damaged national security.
The decision by President Obama to cancel his meeting with his Russian counterpart is a sign of deepening tensions between the two countries, which have clashed on a number of other key issues, most notably the Syrian civil war. Russia is a staunch ally of embattled Syrian President Bashar al-Assad, whilst the US has aligned itself - though somewhat hesitantly - with the rebel Free Syrian Army that is fighting to oust Assad.