Andy Chan Ho-tin (center), the founder of the Hong Kong National Party, is surrounded by members of the media as he leaves the Foreign Correspondents' Club in Hong Kong on August 14, 2018.

A pro-independence Hong Kong politician whose party is under threat of a ban lashed out at China in a closely watched Tuesday speech, drawing immediate criticism from local authorities.

Andy Chan Ho-tin, a member of the Hong Kong National Party, has been at the center of controversy over free speech and Hong Kong's autonomy. The Foreign Correspondents' Club of Hong Kong, which invited him, came under pressure itself from the central government in Beijing as well as local authorities to cancel the event.

Dozens of protesters gathered outside the club in central Hong Kong amid heavy police presence as what appeared to be mostly anti-independence demonstrators held up signs and shouted slogans.

Hong Kong enjoys rights not allowed in mainland China, such as the freedom to criticize political leaders, but the central government and local authorities has drawn a red line at calls for independence and has pressured local leaders to back that up.

In his speech, Chan said his party has been "demonized as some sort of extremist group" by China for advocating independence and that he has come under harsh surveillance by authorities.

"In reality, what the National Party is chasing after is no different from what many Hong Kongers wish for: the dream of democracy," Chan said.

In comments likely to anger the central government, Chan said that Hong Kong, with its distinctive language, culture and history, is coming under the same pressure to assimilate with the nation as minority groups in the mainland.

He cited the far western region of Xinjiang, which he referred to as East Turkestan, as well as Tibet. East Turkestan is a political term that sometimes refers to Xinjiang and was also used in a short-lived East Turkestan Republic in the 1930s.

"China is a large empire," Chan said. "If you are different, you are wrong."

Police have requested that Chan's party be banned on national security grounds and authorities are going through the process of making a decision, which includes hearing the party's defense.