HONG KONG (Reuters) - Pressure is mounting on a Hong Kong academic who helped lead pro-democracy protests in 2014, as dozens of pro-Beijing groups ran newspaper advertisements on Tuesday to demand his dismissal for allegedly advocating independence from China.

FILE PHOTO - Benny Tai, a founder of the Occupy Central movement, surrounded by supporters, walks into the police headquarters in Hong Kong, China March 27, 2017. REUTERS/Bobby Yip/File Photo

The former British colony returned to Chinese rule in 1997 under a so-called “one country, two systems” formula that guarantees it a high degree of autonomy and far greater freedoms than exist on the mainland.

Beijing, which considers the freewheeling financial hub an “inalienable” part of China, has been extremely critical of recent calls by more radical activists for greater self-determination for Hong Kong, and even outright independence.

Comments by law professor Benny Tai at a forum in Taiwan last month drew the ire of the People’s Daily, China’s mouthpiece newspaper, which urged Hong Kong authorities on Monday to take legal action against him under existing laws.

The Hong Kong government also condemned Tai, saying in a statement it was “shocked by the remarks made by a university teaching staff member that Hong Kong could consider becoming an independent state”.

The latest salvo came from the Federation of Hong Kong Shenzhen Associations, a pro-Beijing group of nearly 70 bodies, which took out full-page advertisements in several newspapers, including the pro-Beijing Ta Kung Pao.

In the advertisements, the federation, backed by 68 clan and patriotic groups and businesses, urged Tai’s employer, the University of Hong Kong, to fire him immediately.

It also called for independence advocates to be “legally regulated”.

It gave no specifics, but the call adds to a growing clamor from pro-Beijing voices in the city for harsher national security laws to tighten regulation of those advocating independence as a possible “subversive” act against China.

Tai did not immediately respond to telephone calls from Reuters to seek comment.

Tai told Hong Kong’s public broadcaster RTHK he had the right to free speech, and his comments were taken out of context.

He said he did not support independence for Hong Kong, and had only been speaking hypothetically that Hong Kong might consider becoming independent, should China one day become democratic.

Pro-democracy politicians and a group of liberal academics also condemned the criticism against Tai, saying Hong Kong’s laws grant any individual the freedom to comment on political matters, even independence.