The government charged that the F.B.I. employee, Kun Shan Chun, had "expressed a willingness to facilitate the passage of sensitive United States government information" to his Chinese associates, including some with connections to the Chinese government.

Federal prosecutors in Manhattan said that Mr. Chun had also made a series of false statements to the bureau regarding his contact with these Chinese nationals and a firm based in China, Zhuhai Kolion Technology Company, "as part of a longstanding and concerted effort to conceal these relationships."

Mr. Chun, who is known as Joey and who works in the F.B.I.'s New York office, pleaded guilty on Monday before a federal magistrate judge in Manhattan to one count of acting in the United States as an agent of China. The count carries a maximum term of 10 years.