New slides detail how NSA collects data from US internet firms

The Washington Post has released four previously unpublished slides from the National Security Agency's PowerPoint presentation on Prism, the top-secret programme that collects data on foreign surveillance targets from the systems of nine participating internet companies.

The newly published top-secret documents, which the newspaper has released with some redactions, give further details of how Prism interfaces with the nine companies, which include such giants as Google, Microsoft and Apple.

According to annotations to the slides by the Washington Post, the new material shows how the FBI "deploys government equipment on private company property to retrieve matching information from a participating company, such as Microsoft or Yahoo and pass it without further review to the NSA".

The new slides underline the scale of the Prism operation, recording that on April 5 there were 117,675 active surveillance targets in the programme's database. They also explain Prism's ability to gather real-time information on live voice, text, email or internet chat services, as well as to analyse stored data.

The 41-slide PowerPoint was leaked by the former NSA contractor Edward Snowden to The Guardian and the Washington Post, with both news organisations publishing a selection of the slides on June 6.

Several of the participating companies listed on the third new slide released by the Washington Post - Microsoft, Yahoo, Google, Facebook, PalTalk, YouTube, Skype, AOL and Apple - denied at the time of the initial publication that they had agreed to giving the NSA direct access to their systems. Google told The Guardian that it did not "have a back door for the government to access private user data".