Edward Snowden, the former U.S. government contractor who leaked secret details of official surveillance programs, pledged Monday to release more information about U.S. intelligence-gathering methods that he described as “nakedly, aggressively criminal.”

“All I can say right now is the U.S. government is not going to be able to cover this up by jailing or murdering me,” Snowden wrote in an online chat hosted by Britain’s Guardian newspaper. “Truth is coming, and it cannot be stopped.”