An ex-CIA agent has pleaded guilty to spying for China, the US justice department says, in a case believed to be linked to the dismantling of a US espionage network.
Jerry Chun Shing Lee, 54, left the CIA in 2007 to live in Hong Kong, where he was recruited by Chinese agents.
Prosecutors say the naturalised US citizen was then paid to divulge information on US covert assets.
This led China to bring down a network of informants between 2010 and 2012.
About 20 informants were killed or jailed during that period - one of the most disastrous failures of US intelligence in recent years.
The US Assistant Attorney General for National Security, John Demers, said Lee's case was the third involving US agents and China in less than a year.
"Every one of these cases is a tragic betrayal of country and colleagues," he said.