China’s Foreign Ministry has attempted to block a planned address by a pro-independence activist in Hong Kong, in the latest sign that Beijing’s tolerance is wearing thin for pro-democratic discourse in the semi-autonomous financial hub.

Andy Chan Ho-Tin, the 27-year-old convener of a political party that advocates for the territory’s independence from China, was scheduled to speak next week at the Foreign Correspondents Club Hong Kong, an internationally recognized hub for professional journalists and a regional stronghold of free speech.

News website Hong Kong Free Press reported that a representative of China’s Ministry of Foreign Affairs urged the club, known by its acronym FCC, “to reconsider its decision” to host Chan, whose Hong Kong National Party is being scrutinized by local authorities and faces potentially being banned because its pro-independence platform could constitute a national security threat.

FCC acting president Victor Mallet confirmed to TIME that a representation was made, emphasizing that the club regularly hosts a diverse range of voices and opinions, and welcomes the views of both the Hong Kong and Chinese governments on issues of public importance.

“Our position is that we are a club that is a very strong defender of freedom of the press, and freedom of speech,” Mallet said. “We provide a platform and a venue for speakers of many different political views and opinions.”

Speaking to TIME Friday, Chan said trying to block the event amounted to an attempt by China to “colonize Hong Kong.”

“[The Chinese government is] restraining journalists from reporting news to the international society,” Chan said, “just like how they do it in China.”

Read more: Hong Kong Makes History With First Pro-Independence Rally

An official flyer for the event said the talk would cover a brief history of Chan’s HKNP party, “and touch on what Mr. Chan feels it means to be at the helm of a movement trying to construct a national identity for Hong Kong, and his reaction to the strong pushback from the government faced by his party.”

Last month, police advised the Hong Kong government that a case could be made to ban Chan’s party under an obscure national security provision. Since a 1997 handover from British rule to Chinese sovereignty, the former colony has maintained a high degree of autonomy and still enjoys a liberal economy and more social and political freedoms than communist China.

But many say Beijing is steadily encroaching; authorities have shown little sympathy for activists and politicians who advocate for democracy in Hong Kong, and no tolerance for those seeking independent nationhood for the territory.

In what could become a precedent-setting case, Hong Kong authorities presented Chan with a dossier containing hundreds of pages of surveillance collected over the past two years and an ultimatum to respond by September.

Get The Brief. Sign up to receive the top stories you need to know right now. Please enter a valid email address. Sign Up Now Check the box if you do not wish to receive promotional offers via email from TIME. You can unsubscribe at any time. By signing up you are agreeing to our Terms of Use and Privacy Policy . This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply. Thank you! For your security, we've sent a confirmation email to the address you entered. Click the link to confirm your subscription and begin receiving our newsletters. If you don't get the confirmation within 10 minutes, please check your spam folder.

Contact us at letters@time.com.