has published new documents revealing that the US National Security Agency (NSA) has spied on world leaders such as Israeli Prime Minister Benjamin Netanyahu, former Italian premier Silvio Berlusconi and UN Secretary General Ban Ki-moon.

The documents released by the organisation show that the NSA eavesdropped on a meeting between Ban and German Chancellor Angela Merkel, who already knew that she had been followed by the USA's intelligence services on other occasions, EFE news reported.

also reported that the NSA had spied on a conversation between Netanyahu and Berlusconi, a meeting between key European Union (EU) and Japanese officials, and a private meeting between Berlusconi, Merkel and former French president Nicolas Sarkozy.

In documents obtained by WikiLeaks, Merkel and Ban talk about how to fight climate change, Netanyahu asks Berlusconi for help in dealing with the US administration led by President Barack Obama, and Sarkozy alerts the former Italian prime minister about dangers of the banking system in his country.

"It will be interesting to see the UN's reaction, because if the secretary general can be targeted without consequence then everyone from world leader to street sweeper is at risk," founder Julian Assange said.

WikiLeaks rose to fame between July and October 2010 by publishing secret documents from the war in Afghanistan (2001) and the second Iraq war (2003), based on leaks from US soldier Chelsea Manning, formerly known as Bradley Manning.