Kun Shan Chun, also known as Joey Chun, was arrested by the FBI in March after an undercover operation, and appeared in a New York court on Monday.
The 46-year old confessed to providing "sensitive" FBI information to an individual with connections to the Chinese government on a number of occasions, the Justice Department said
in a statement.
Originally born in China, Chun was a naturalized U.S. citizen who had been an employee of the FBI for 19 years.
According to the complaint
, Chun tried to recruit an undercover agent to provide him with confidential information, which he said could be exchanged for cash if it was sent to his associates in China.
Chun pleaded guilty to one charge of acting in the United States as an agent of China without providing notice to the Attorney General.
Surveillance, personnel details sent to China
According to the Justice Department
, in 2011 Chun met with a Chinese official during an overseas trip who asked him about his work with the FBI. Chun discussed sensitive information with the official, including telling him the identity of an FBI special agent.
After that meeting, the official repeatedly asked Chun for information about the FBI's internal workings, resulting in Chun transmitting several pieces of sensitive information.
In 2013, Chun sent the official a copy of the FBI organizational chart, with personnel names removed, and in 2015, he sent the same official in China photos of documents detailing surveillance technologies used by the FBI.
The department said Chun also repeatedly attempted to hide his contact with the Chinese government official, lying on forms saying he had no interaction with "foreign contacts."
Chun was granted top security clearance by the FBI in 1998 as part of his job in the FBI's Technical Branch, and during a routine reinvestigation in 2012 the department said Chun made a series of false statements on his declaration forms.
Chun 'violated our nation's trust'
In a statement announcing the outcome, New York Southern District U.S. Attorney Preet Bharara
said, as an American who had worked as a foreign agent, Chun had "betrayed our nation."
"And when the perpetrator is an FBI employee, like Kun Shan Chun, the threat is all the more serious and the betrayal all the more duplicitous," he said.
"Kun Shan Chun violated our nation's trust by exploiting his official U.S. Government position to provide restricted and sensitive FBI information to the Chinese government," Assistant Attorney General for National Security John Carlin said.
Local media reported a statement by Chun's defense attorney Jonathan Marvinny,
in which he said his client regretted his actions.
"The truth is that Mr Chun loves the United States and never intended to cause it any harm," he said.
Chun will be sentenced on December 2.