Classified documents revealed by whistleblower Edward Snowden have thrown light on another secret surveillance program by US' National Security Agency which allows analysts to develop intelligence from the internet.
The 'XKeyscore' program considered as the 'widest-reaching' system allows analysts to search with no prior authorization through vast databases containing emails, online chats and the browsing histories of millions of individuals, the Guardian reports.
The report said that analysts can collect data by filling in a simple on-screen form giving only a broad justification for the search and the request is not reviewed by a court or any NSA personnel before it is processed.
According to the revealed documents an NSA tool called DNI Presenter, used to read the content of stored emails, also enables an analyst using XKeyscore to read the content of Facebook chats or private messages.
Meanwhile, the NSA documents assert that by 2008, 300 terrorists had been captured using intelligence from XKeyscore and it insists that XKeyscore is used as a part of NSA's lawful foreign signals intelligence collection system and is fully auditable to ensure they are within the law.
The NSA further said that these types of programs allow the agency to collect the information in order to defend the nation and to protect US and allied troops abroad, the report added.