The heads of the Senate and House intelligence committees spoke just days after a German lawmaker published a letter from the fugitive and said Snowden was ready to testify to Congress to shed light on "possibly serious offenses."
But Senator Dianne Feinstein, in an interview with CBS' "Face the Nation" news show, said he had missed his chance to do so.
"He had an opportunity, if what he was was a whistle blower to pick up the phone and call the House Intelligence Committee, the Senate Intelligence Committee and say, 'Look, I have some information you ought to see,'" Feinstein said.
"And I think the answer is no clemency," she said, adding that Snowden should be prosecuted.
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The former National Security Agency (NSA) contractor was granted asylum in Russia in August to the fury of the United States, where he is wanted on espionage charges.
Congressman Mike Rogers, a Republican, said he didn't see "any reason" to grant Snowden clemency.
"If he wants to come back and own up to the responsibility of the fact that he took and stole information, he violated his oath, he disclosed classified information ... I'd be happy to have that discussion with him," he told CBS in a separate interview.
German Green party lawmaker Hans-Christian Stroebele met with Snowden late Thursday at an undisclosed location in Moscow to discuss his disclosure that Washington monitored German Chancellor Angela Merkel's cell phone, a matter that has caused an uproar in Europe.
In the letter he passed to Stroebele, Snowden said he was prepared to provide details of US spying to Germany and was "heartened" by the global response to his leaks despite unrelenting US pressure.