SINGAPORE -Academic Huang Jing has resigned as an independent director of Keppel Land with immediate effect.

This comes after his permanent residency was cancelled on Friday, for working with a foreign government to influence Singapore's foreign policy and public opinion here.

The Ministry of Home Affairs had earlier announced that Huang Jing and his wife Shirley Yang Xiuping, who are United States citizens, will be permanently banned from Singapore, in what is the first publicly known case of its kind in nearly two decades.

MHA said in a statement that Dr Huang has been identified as "an agent of influence of a foreign country" who worked with intelligence organisations and agents from that country. It did not name the country.

The 60-year-old was also the director of the Centre on Asia and Globalisation and Lee Foundation Professor on US-China relations at the Lee Kuan Yew School of Public Policy (LKYSPP), which is part of the National University of Singapore (NUS).

The NUS has suspended him without pay while the university works with the Home Affairs Ministry.

An NUS spokesman said earlier that his employment was conditional on him having the necessary work permits.