The White House said there may need to be additional constraints placed on America's spy agencies after a series of embarrassing disclosures about the broad scope of US intelligence gathering.
"We recognize there needs to be additional constraints on how we gather and use intelligence," said White House spokesman Jay Carney.
The White House has said its review of US intelligence-gathering procedures will be completed by the end of the year.
More top news
Fans can finally have their first look at Jared Leto's incarnation of the classic villain in 2016's Suicide Squad
Labour is promising to reverse the Conservative policy of privatisation in the NHS which it claims is creating longer waiting times.
The Queen and senior members of the monarchy will attend services around the world to commemorate the centenary of the battle of Gallipoli.