The White House and top US lawmakers have rejected clemency for the fugitive intelligence analyst Edward Snowden.
"Mr Snowden violated US law. He should return to the US and face justice," said White House adviser Dan Pfeiffer.
Mr Snowden asked for international help to persuade the US to drop spying charges against him in a letter given to a German politician.
Mr Snowden, 30, fled to Russia in June after leaking details of far-reaching US telephone and internet espionage.
He was granted temporary asylum, allowing him to live in Russia until July 2014.