US intelligence agencies will see a 5% drop in funding under a proposed 2015 budget, officials have said, after a year marked by controversy over far-reaching electronic spying.

Director of National Intelligence James Clapper said yesterday the requested budget for most of the country's 17 spy services came to $45.6 billion for fiscal year 2015, which begins October 1.

The proposed budget, which must be approved by Congress, is lower than the 2014 national intelligence program budget, at $48.2 billion.

The Pentagon is also planning for a slight drop in funding for intelligence activities that support the military, requesting $13.3 billion for next fiscal year, officials said.

The 2014 budget had allocated $14 billion for the military intelligence program.

In keeping with past practise, Clapper's office, or ODNI, did not divulge any further details or provide a breakdown of the budget.

"Any and all subsidiary information concerning the National Intelligence Program budget, whether the information concerns particular intelligence agencies or particular intelligence programs, will not be publicly disclosed," ODNI said in a brief statement.

Given the secrecy surrounding America's spy agencies and their funding, it remains unclear if the fallout from ex-intelligence contractor Edward Snowden's leaks has had any impact on the National Security Agency's 2015 budget.

The trove of classified files disclosed by Snowden since June included documents - leaked to The Washington Post - that shed some light on the so-called "black budget" that funds for different spy operations and programs.

The documents gave a breakdown on proposed intelligence spending for 2013, with the CIA budget ranking first at $14.7 billion, followed by the NSA at $10.8 billion and the National Reconnaissance Office at $10.3 billion.

The NRO operates America's network of spy satellites.