Leaker Edward Snowden accused the National Security Agency of targeting reporters who wrote critically about the government after the 9/11 attacks and warned it was “unforgivably reckless” for journalists to use unencrypted email messages when discussing sensitive matters.

Snowden said in an interview with the New York Times Magazine published Tuesday that he came to trust Laura Poitras, the documentary filmmaker who, along with Guardian reporter Glenn Greenwald, helped report his disclosure of secret surveillance programs, because she herself had been targeted by the NSA.

“Laura and [Guardian reporter] Glenn [Greenwald] are among the few who reported fearlessly on controversial topics throughout this period, even in the face of withering personal criticism, and resulted in Laura specifically becoming targeted by the very programs involved in the recent disclosures,” Snowden said for the article, a profile of Poitras.

Snowden didn’t detail how Poitras was targeted by the NSA surveillance programs he disclosed, but suggested the agency tracked her emails and cautioned other journalists that they could be under surveillance.

“I was surprised to realize that there were people in news organizations who didn’t recognize any unencrypted message sent over the Internet is being delivered to every intelligence service in the world,” he said. “In the wake of this year’s disclosures, it should be clear that unencrypted journalist-source communication is unforgivably reckless.”

Snowden, who at one point in the interview referred to himself as “famously paranoid,” said he came to trust Poitras because she was one of the few journalists “to challenge the excesses of the government” during a time of “heightened nationalism.”

“After 9/11, many of the most important news outlets in American abdicated their role as a check to power – the journalistic responsibility to challenge the excesses of government – for fear of being seen as unpatriotic and punished in the market during a period of heightened nationalism,” he said.