Washington, Aug 30 (IANS): The US secret intelligence budget has gone up greatly since the 9/11 terrorist attack more than a decade ago, a media report said.

The reason behind this is the aggressive new efforts made to hack into foreign computer networks, the Washington Post reported Thursday citing new documents revealed by former defence contractor Edward Snowden.

The newspaper said the US spy agencies have built "an intelligence-gathering colossus" since the attacks of Sep 11, 2001, but remained unable to provide critical information to the US president on a range of national security threats, Xinhua reported.

The "black budget" for the fiscal year 2013, for instance, totalled $52.6 billion, about twice the estimated size of the 2001 budget and 25 percent above that of 2006.

According to a 178-page budget summary for the National Intelligence Programme, the US intelligence community consists of 16 spy agencies with 107,035 employees.

Spending by the Central Intelligence Agency (CIA) has grown up to $14.7 billion in 2013, more than any other spy agency and nearly 50 percent above that of the National Security Agency (NSA), which has been under fire at home and abroad for secret spying programmes revealed by Snowden.

In a response to inquiries from the Washington Post, US Director of National Intelligence James Clapper admitted the US has made "a considerable investment in the Intelligence Community" since the terrorist attacks of Sep 11, 2001.

The documents also showed that both the CIA and NSA have launched new "offensive cyber operations" to hack into foreign computer networks to steal information or sabotage enemy systems.