Edward Snowden, the former U.S. spy agency contractor who leaked details of the government’s mass surveillance programs, has weighed in on Hillary Clinton’s use of a private email server in her home for her work as secretary of state.

He is not impressed, he said in an interview with Al Jazeera, due to be broadcast in full on Friday, suggesting a double standard is at play.

“Anyone who has the clearances that the secretary of state has or the director of any top level agency has knows how classified information should be handled,” he said in an extract of the interview published on Thursday.

“If an ordinary worker at the State Department or at the Central intelligence Agency or anything like that were sending details about … meetings with foreign government officials and the statements that were made to them in confidence over unclassified email systems, they would not only lose their jobs and their [security] clearance, they would very likely face prosecution.”

Clinton maintains she did nothing wrong: she did not send or receive any information on her email server that was marked classified, she has said. The Federal Bureau of Investigation is examining her server to see whether information that passed through it was mishandled.

Snowden was speaking from Russia, where he has been granted asylum after the U.S. Department of Justice charged him with stealing government property and violating the Espionage Act. Snowden said he was acting as a whistleblower, and his leaks prompted legal reforms in the United States limiting mass surveillance. He has said he will return to the U.S. to faces charges if he allowed to mount a “public interest” defense.

Clinton has said Snowden’s leaks harmed national security, and has criticized his fleeing the U.S. before his leaking of the documents became public.