The U.S. embassy has said they are worried about the citizen's welfare.
The greater the difficulty, the more there were strong reasons to suspect Page worked with Russian spies.
China is offering rewards of up to 500,000 yuan ($72,000) to citizens who help catch foreign intelligence agents.
State Department employee Candace Marie Claiborne has been arrested for selling top secret diplomatic data to Chinese spies and trying to cover up the affair.
Six others given death penalty alongside the former president as Egypt continues crackdown on the Muslim Brotherhood.
Fed records show several incidents were described internally as "espionage."
Kim Dong Chul, 62, was arrested in North Korea in October.
U.S. officials, speaking on condition of anonymity, identified the suspect as Lieutenant Commander Edward Lin.
Unidentified officer in sensitive intelligence unit could possibly face the death penalty.
Closed society has used detained Americans to force contact with the United States.
The plan, code-named Nitro Zeus, was aimed at damaging Iran's air defenses, communications and power grid.
Bill Evanina said he had seen "no indication...that anything has changed."
They helped peddle more than $30 million worth of electronics frequently used in missile guidance systems, among other things.
The Post reacted strongly to the conviction Sunday night.
The prosecution of a Washington Post journalist shows the ruling mullahs' contempt for Western values.
Jason Rezaian has been charged with espionage for collecting confidential information.
The six allegedly worked together to steal source code and other proprietary information from two companies that develop technology often used in military technologies