WASHINGTON — Attorney General Eric H. Holder Jr. said Thursday that the United States was willing to discuss how the criminal case against Edward J. Snowden would be handled, but only if Mr. Snowden pleaded guilty first.

Mr. Holder, speaking at a question-and-answer event at the University of Virginia, did not specify the guilty pleas the Justice Department would expect before it would open talks with Mr. Snowden’s lawyers. And the attorney general reiterated that the United States was not willing to offer clemency to Mr. Snowden, the former National Security Agency contractor who has leaked documents that American officials have said threaten national security.

“Instead,” Mr. Holder said in response to a question at the university’s Miller Center, “were he coming back to the U.S. to enter a plea, we would engage with his lawyers.”

Calls for clemency for Mr. Snowden, who has taken refuge in Moscow, have increased in the last several months as some civil liberties groups and prominent news organizations, including an editorial in The New York Times, have asked the government to consider such a move.