US Secretary of State John Kerry says some National Security Agency spying has gone too far and says it will be stopped.
Mr Kerry says that because of modern technology, some NSA activities have been happening on "automatic pilot" without Obama administration officials knowing.
He says current reviews of US surveillance work will ensure that technology is not being abused and says the Obama administration is going to make sure activities that have, "reached too far" do not happen in the future.
Sweeping surveillance practices by the NSA have sparked anger in other nations, who have called for investigations and have demanded the US stop spying on allies.
Mr Kerry spoke via video link to an open government conference in London.