Washington, Sep 1 (IANS): Newly disclosed secret documents have shown that the US spy agencies conducted 231 cyber attacks in 2011, media reports said.

Documents revealed by former CIA defence contractor Edward Snowden show that the scope and scale of Washington's cyber-attacks have been growing as US intelligence services break into and disrupt computer networks in other countries, Iran's Mehr news agency reported citing the Washington Post.

The documents obtained by the Washington Post were part of a multi-volume intelligence budget which showed the US has built an "intelligence-gathering colossus" with a whopping black budget of $52.6 billion for the current fiscal year.

The budget documents also disclosed a $652 million project, code-named "GENIE", under which US computer specialists infiltrate foreign networks in order to bring them under secret US control.

The administration of US President Barack Obama refuses to acknowledge such US cyber attacks and treats the operations as clandestine, the report said.

According to a US presidential directive issued in October 2012, a cyber operation is considered offensive when it is intended "to manipulate, disrupt, deny, degrade, or destroy information resident in computers or computer networks, or the computers and networks themselves".

The presidential policy directive requires US military cyber attacks to be approved by the president. However, the Washington Post reports, the directive largely does not apply to the US intelligence community.

The documents obtained by the Washington Post also show that US cyber attacks sometimes involve "field operations" overseas, conducted with the help of CIA operatives or secret military forces. Such "field operations" were an attempt to physically place hardware implants or software modifications.