(Telecompaper) Google has denied any involvement in a secret US government program called PRISM to give the National Security Agency direct access to its servers. In a statement on the company's official blog, CEO Larry Page and chief legal officer David Drummond write that the company has not joined any such programme and that the government does not have direct or "back door " access to information store in Google's data centres. Similar statements were made by Facebook, Yahoo and Microsoft. Separately, a former CIA employee, Edward Snowden, has identified himself as the source of the intelligence leaks to the Guardian and Washington Post. He said he disclosed the documents to make public what he called a systematic surveillance of innocent citizens.