What defence contractor Edward Snowden has exposed so far is just the tip of the iceburg and the US government should hope nothing bad happens to him. According to a Glenn Greenwald, the Guardian journalist who first published the Snowden documents, that he had some information which really could do some harm to the US.

"The US government should be on its knees every day begging that nothing happen to Snowden, because if something does happen to him, all the information will be revealed and it could be its worst nightmare," she said.

Snowden has placed data all over the internet with people instructed to release it if anything happens to him or he is arrested. For example Snowden has tucked away information about how the US. spy programs capture transmissions in Latin America and how they work.

"One way of intercepting communications is through a telephone company in the United States that has contracts with telecommunications companies in most Latin American countries," Greenwald said.

So far his leaks on US spying secrets, including eavesdropping on global email traffic, have upset Washington's friends and foes and created a real mess for the Obama administration.