"I assure you innocent people are not being abused in this process, but there's an effort to try to gather information. And yes, in some cases, it has reached too far inappropriately," Kerry told a London conference on 'Open Government Partnership Annual Summit' through video link.
"And the President, our President is determined to try to clarify and make clear for people and is now doing a thorough review in order that nobody will have the sense of abuse," Kerry said.
News reports that the US is spying on millions of people is not true, he said.
The US is facing criticism from international leaders over revelations that the National Security Agency carried out electronic surveillance and snooped in on conversations of 35 world leaders, including German Chancellor Angela Merkel.
"Just the other day it was – there was news in the papers of 70 million people being listened to. No, they weren't. It didn't happen," he said.
"There's an enormous amount of exaggeration in this reporting from some reporters out there. What we're trying to do is in a random way find ways of trying to learn if, in fact, there is a threat that we need to respond to," he said.
"In some cases, I acknowledge to you, as has the President, that some of these actions have reached too far, and we are going to make sure that does not happen in the future," he said.
Kerry said the surveillance programmes of the US and many other countries have been highly successful and has resulted in preventing many a terrorist attack.
"We have actually prevented airplanes from going down, buildings from being blown up and people from being assassinated because we've been able to learn ahead of time of the plans," he said.