Michael Hayden: NSA will have to be more transparent
18 December 2013 Last updated at 22:31 GMT
A presidential panel convened by the White House has recommended significant curbs on the National Security Agency's surveillance programmes.
Among its 46 recommendations, the five-member panel said the NSA should cease storing vast amounts of data on calls processed by US phone companies, and called for limits on intelligence agencies' ability to compel companies to provide telephone call data.
Former NSA director Michael Hayden told the BBC's Katty Kay that although he supports increased transparency at the agency he ran until 2005, some of the reforms, if implemented, would make intelligence gathering more difficult.
"Making this more public will shave points off of operational effectiveness," he said. But he said, "if we don't do that it won't matter because the American people won't let us do it in the first place."