Russian authorities have charged a former U.S. Navy officer with espionage after holding him in a Moscow prison for more than a week, saying he had tried to obtain military secrets, officials said.

The U.S. Embassy has identified the American as Edmond Pope, but Russian authorities have consistently refused to identify him or a Russian man arrested as an alleged accomplice.

A spokesman with the Federal Security Service, Russia's main intelligence agency, said the American faces up to 20 years in prison if convicted. The Russian was charged with divulging state secrets and faces 10 years behind bars.

The agency, known by the initials FSB, said it had found documents proving the American had cultivated contacts with Russian scientists in an effort to buy state secrets. Russian television agencies said he was arrested after paying for plans of a submarine-launched missile.

Pope is being held in Moscow's Lefortovo prison, where he has been visited by U.S. diplomats, U.S. Embassy officials said. A Russian lawyer has been appointed for him.

A woman reached at Pope's home in State College, Pennsylvania, who asked not to be identified, said that the family was not prepared to comment on the charges.

Pope is a native of Grants Pass, Oregon. After retiring from the Navy, Pope worked in 1994-97 with Pennsylvania State University's Applied Research Laboratory, which does research for the military.

Pope was an "assistant for foreign technology" who developed contacts between Russian and U.S. research institutes and worked on converting technology for commercial uses, a statement from Penn State said.

He left the laboratory to create CERF Technologies International, which "has commercial contacts with organizations in Russia," according to the statement. He frequently traveled to Russia on business, it said.

A friend of Pope's who has kept in touch with him said in a recent newspaper interview that Pope had been concerned he might be framed for his work.

Richard Penny said Pope told him he was being constantly contacted by Russians seeking American cash.

"He said he had a hard time sleeping at night because people were always knocking on his door asking him to buy things," Penney was quoted as saying by the Daily Courier in Grants Pass. "He realized he could be set up."

So far, the reaction to Pope's case has been muted, with neither Russia or the United States commenting as much as they did during a string of arrests of alleged spies last year.