BANGKOK — Singapore has ordered the expulsion of a noted American academic for what it said was his covert effort to influence Singapore’s foreign policy on behalf of an unnamed foreign government.

The academic, Huang Jing, was accused of passing “privileged information” to senior Singapore officials with the intent of affecting their decisions. He was quickly removed from his position as the Lee Foundation professor on United States-China relations at the Lee Kuan Yew School of Public Policy.

“He did this in collaboration with foreign intelligence agents,” the Singapore Ministry of Home Affairs said in a statement on Friday that announced the order. “This amounts to subversion and foreign interference in Singapore’s domestic politics.”

Mr. Huang has held posts at the Brookings Institution, Stanford University and Harvard University. Some view his academic writings as pro-Chinese.