Sepp Blatter has challenged his critics to prove that he is corrupt, and insists that anybody who accuses him of guilt by association to the corruption scandal engulfing world football's governing body "should go to jail."
Blatter announced on June 2 he would step down as FIFA president at an extraordinary congress to be held between December and March.
It followed the crisis in late May which saw 14 people indicted in the United States on football-related corruption charges.
But the 79-year-old cast uncertainty over his intentions last week when he said: "I have not resigned, I put my mandate in the hands of an extraordinary congress."
Blatter has been urged to stop "flirting with power" by Domenico Scala -- the man who will oversee the next FIFA presidential election -- but maintained his innocence in an interview with German magazine Bunte.
"I have a clean conscience," he said. "If somebody accuses me of being corrupt, I ask him whether he knows the meaning of that word. Whoever calls me corrupt will have to prove it, but nobody can prove that because I am not corrupt.
"I am open to correct or positive criticism. I can use that to reconsider if I need to change in the future. But if anybody calls me corrupt because FIFA is corrupt, I can only shake my head. Everybody who says something like that should go to jail.
"My faith has given me strength during the last week. I am a religious person and pray, too. I own a golden cross that has been blessed by Pope Francis. I believe I will go to heaven one day. But I believe there is no hell. I disagree with the pope on that."
Blatter is himself reportedly under investigation by the FBI and will not attend the Women's World Cup final in Canada this week due to the twin investigations by American and Swiss justice authorities.
Blatter would normally attend the final and hand over the trophy to the captain of the winning team.
The Swiss attorney general is also investigating the bidding process for the 2018 and 2022 World Cups.
ESPN FC correspondent Jens Weber contributed to this report.