The US government released an email Thursday written by Edward Snowden, in a bid to debunk his claim that he raised concerns about mass spying programs before fleeing and engineering huge media leaks.
Snowden, now exiled in Russia, said in an interview aired by NBC Wednesday that he had gone through official channels to question the legality of National Security Agency surveillance.
The former intelligence contractor mentioned a specific email he said he had written to the NSA General Counsel's Office detailing his concerns.
In response, the agency released what the Obama administration said was the only such communication found in the archives from Snowden on the issue, and said it did not prove his claims.
In the April 2013 email, Snowden asked NSA lawyers to clarify a question about the relative authority of executive orders released by the president and legal statutes.
The exchange does not in itself appear to register a complaint or concern about the mass phone data surveillance programs that he later exposed in a series of leaks to media organizations.
"The email did not raise allegations or concerns about wrongdoing or abuse but posed a legal question that the Office of General Counsel addressed," White House spokesman Jay Carney said.
"There was not additional follow-up noted."
The government's contention that the email was the only one from Snowden to the office of the General Counsel could not be independently verified.
It was also unclear whether there were further emails sent by Snowden to other officials or offices within the NSA that the secretive agency did not release.
The White House maintains there were plenty of avenues Snowden could have taken to raise concerns about the legality and scope of NSA programs instead of leaking huge amounts of classified material to journalists.
"The appropriate authorities have searched for additional indications of outreach from Mr. Snowden in those areas and to date have not found any engagements related to his claims," Carney said.
But Snowden maintained in the interview that he did go through official channels.
"The NSA has records, they have copies of emails right now to their Office of General Counsel, to their oversight and compliance folks, from me raising concerns about the NSA's interpretations of its legal authorities," he said.
"The response more or less, in bureaucratic language, was, 'You should stop asking questions.'"
Snowden also told NBC he was open to the possibility of clemency or amnesty and would like to return home one day.
But he maintained he had carried out a patriotic act by exposing huge surveillance dragnets he said infringed the US Constitution.
The Obama administration, however, says Snowden is welcome to return home but only to face trial for exposing sensitive top secret information it says aided US enemies.