A decorated US Navy officer faces espionage and other charges after allegedly passing defense secrets to China and Taiwan -- and possibly other nations, a US official said Monday.

Speaking on condition of anonymity, the official told AFP the sailor is Lieutenant Commander Edward Chieh-Liang Lin, who has been in the Navy since 1999 and has won several awards including two Navy/Marine Corps Commendation Medals.

The Navy declined to confirm his identity, but provided a heavily redacted copy of a charge sheet that outlined four charges against an officer of Lin's rank.

According to that document, the suspect communicated "secret information relating to the national defense to representatives of a foreign government."

The US official said Lin is accused of handing secret information over to China and Taiwan, adding it was possible the investigation could also uncover ties to other countries.

A 2008 Navy article says Lin left his birthplace of Taiwan when he was 14 and eventually became a naturalized US citizen.

A Navy biography shows Lin underwent training as a nuclear specialist between 2000 and 2002, when he was still enlisted.

The charges say the accused was later assigned to the Navy's Commander Patrol and Reconnaissance Group, which gathers intelligence.

The officer is also accused of violating a lawful general order by "wrongfully failing to properly store material classified as secret."

- Prostitution charge -

A third charge alleges he lied about which foreign country he was going to visit while on leave, and he was also alleged to have committed adultery and procured a prostitute, with "such conduct being... of a nature to bring discredit upon the armed forces."

The Navy declined to provide the name of the accused's attorney, and additional attempts to find his lawyer were not immediately successful.

It was not clear how long Lin faces in prison if convicted, though the alleged offenses are "not capital."

Lin appeared before a preliminary Article 32 hearing on Friday, during which a military judge hears initial evidence and then recommends to a commanding admiral whether the case should be referred to a full court-martial.

Lin remains in custody at the naval brig in Chesapeake, Virginia.

The case emerges amid heightened tensions between China and regional neighbors in the South China Sea, where Beijing is building massive military structures including radar systems and an airstrip over reefs and tiny islands.

China claims almost all of the contested sea, which is important for international shipping and is believed to hold valuable mineral and energy deposits.

Neighboring countries and Washington fear China could impose military controls over the entire South China Sea.

The United States also suspects Beijing is conducting cyber attacks on US interests and passing this information to the private sector for commercial gain.