A former CIA officer could spend the rest of his life behind bars after pleading guilty to spying for China, the US Justice Department said.
Jerry Chun Shing Lee, 54, was arrested in January 2018, suspected of having provided information on a CIA network of informants that was brought down by China between 2010 and 2012.
Lee pleaded guilty before a US District Court judge in the Eastern District of Virginia to conspiring to provide national defence information to China, the department said in a statement.
Lee, a former CIA case officer, left the Central Intelligence Agency in 2007 and moved to Hong Kong.
According to the Justice Department, he was approached by two Chinese intelligence officers in April 2010.
They offered to pay Lee $100,000 for information and to take care of him "for life" in exchange for his cooperation, it said.
The Justice Department said that in May 2010, Lee created a document on his laptop that described where the CIA assigns officers and the "particular location and timeframe of a sensitive CIA operation."
It said the FBI had also recovered handwritten notes made by Lee related to his work for the CIA.
"These notes included, among other things, intelligence provided by CIA assets, true names of assets, operational meeting locations and phone numbers and information about covert facilities," the Justice Department said.
John Brown, the FBI's assistant director for counterintelligence, said that Lee's actions had "dangerous ramifications".
"By knowingly aiding a foreign government, Mr Lee put our country's national security at serious risk and also threatened the safety and personal security of innocent people, namely his former intelligence colleagues," Mr Brown said.
FBI Director Christopher Wray said last week that China poses the most serious intelligence threat to the United States.
Speaking at the Council on Foreign Relations (CFR) in Washington, Mr Wray said China poses a "multi-layered" threat to US interests.
"They're doing it through Chinese intelligence services, through state-owned enterprises, through ostensibly private companies, through graduate students and researchers, through a variety of actors all working on behalf of China," he said.
Lee is to be sentenced on 23 August. He faces a maximum sentence of life in prison.