National Security Agency leaker Edward Snowden on Thursday said he acknowledged the need for some surveillance, saying that “not all spying is bad.”

Snowden made the remark during a live chat in which he fielded questions from Twitter.

The former government contractor, whose disclosures of classified information detailing secret NSA surveillance programs sparked a debate over the balance between national security and privacy rights, was asked what he believed the “appropriate extent” of U.S. surveillance should be.

Snowden said that with the technology available to the intelligence community more should be done to ensure that only the communications of those suspected of wrongdoing were monitored.

“The biggest problem we face right now is the new technique of indiscriminate mass surveillance, where governments are seizing billions and billions and billions of innocents’ communication every single day,” said Snowden. “This is done not because it’s necessary — after all, these programs are unprecedented in U.S. history, and were begun in response to a threat that kills fewer Americans every year than bathtub falls and police officers — but because new technologies make it easy and cheap.

“The NSA and the rest of the U.S. intelligence Community is exceptionally well positioned to meet our intelligence requirements through targeted surveillance — the same way we’ve always done it — without resorting to the mass surveillance of entire populations,” he continued.

“When we’re sophisticated enough to be able to break into any device in the world we want to (up to and including Angela Merkel’s phone, if reports are to be believed), there’s no excuse to wasting our time collecting the call records of grandmothers in Missouri.”

President Obama, after a lengthy review of the NSA’s practices, announced new steps last week that he said would better protect Americans’ civil liberties, including requiring secret court warrants before the agency can access collected phone metadata and inviting proposals to store that information outside of the government.

Supporters of NSA spying said that Obama had largely left those programs in place and hailed his decision as a victory. Critics of surveillance say they will press for further reforms and oversight.

Snowden fled to Russia, where he received temporary asylum after leaking the information and is evading espionage and theft charges in the U.S.

Civil libertarians have hailed him as a whistleblower, but many top lawmakers have called him a traitor and question his motives for revealing the nation’s secrets.