WASHINGTON—U.S. authorities said they wouldn't seek the death penalty for former National Security Agency contractor Edward Snowden, but Russian officials said Friday they still wouldn't hand him over to the Americans.

Attorney General Eric Holder wrote his Russian counterpart in the hope of persuading Russia not to grant Mr. Snowden asylum or refugee status. Mr. Holder's letter, dated Tuesday, said any claims by Mr. Snowden that he might face the death penalty or be tortured "are entirely without merit.''

"First, the United States would not seek the death penalty for Mr. Snowden should he return to the United States. The charges he faces do not carry that possibility, and the United States would not seek the death penalty even if Mr. Snowden were charged with additional, death penalty-eligible crimes," Mr. Holder wrote.

Mr. Snowden had been working as a systems administrator at an NSA facility in Hawaii in May when he quietly flew to Hong Kong with a cache of secret documents that exposed details of NSA phone and Internet surveillance programs. He provided some of those documents to reporters, leading to a series of news stories and U.S. criminal charges in June that made him a world-famous fugitive.

On June 23, as Hong Kong and U.S. officials were discussing his possible extradition, Mr. Snowden flew to Moscow. Ever since, he has been holed up in the transit area of a Moscow airport. Several Latin American countries have offered him safe harbor. It's not clear that Mr. Snowden could currently travel to those countries, given his legal status.