Barack Obama announced reforms to the controversial US National Security Agency on Thursday, intended to build "confidence" in the agency after the dramatic revelations of Edward Snowden came to light.

"The NSA actually does a very good job about not engaging in domestic surveillance, not reading people's emails, not listening to ... the contents of their phone calls," said Obama in an interview with Chris Matthews of MSNBC.

More from GlobalPost: NSA tracks cellphones around the world, Snowden documents say

"Outside of our borders, the NSA's more aggressive. It's not constrained by laws. And part of what we're trying to do over the next month or so is having done an independent review and brought a whole bunch of folks, civil libertarians and-- lawyers and others to examine what's being done," said the president.

At the American University interview with MSNBC, Obama added: "I'll be proposing some self-restraint on the NSA and initiating some reforms that can give people some more confidence."

The announcement of impending NSA reforms comes a day after it was revealed that the NSA is tracking cellphones records around the world on an enormous scale — upwards of 5 billion records a day.