Hong Kong (CNN) A senior British journalist denied a work visa by the Hong Kong authorities was barred from entering the city as a tourist Thursday, in the same week a talk by exiled Chinese dissident writer Ma Jian was canceled, raising new fears over press freedoms in the semi-autonomous Chinese city.

Financial Times Asia editor Victor Mallet was turned away at the border after several hours of questioning by immigration officers, the newspaper said, weeks after his working visa renewal was controversially refused

Under current immigration rules, British nationals are typically allowed into Hong Kong without a visa, after which they are permitted to stay for 180 days.

Hong Kong's refusal to grant Mallet entry as a tourist effectively places him on a blacklist.

The Financial Times is currently appealing the earlier decision, which was widely seen as a response to Mallet hosting a talk by a pro-Hong Kong independence activist in his role as acting President of the Foreign Correspondent's Club.

Hong Kong Chief Executive Carrie Lam has said it was "pure speculation" to connect Mallet's expulsion with the August talk by Hong Kong National Party (HKNP) founder Andy Chan, whose organization was later banned.

"As a rule, not only locally, but internationally, we will never disclose, the Immigration Department will not disclose the individual circumstances of the case or the considerations of his decision," she added.

Victor Mallet, a Financial Times journalist, speaks at an event hosted by the Foreign Correspondents' Club (FCC) in Hong Kong, August 14, 2018.

When asked whether media organizations could face repercussions if they interviewed pro-independence figures in the future, Lam responded by referring to the Basic Law, Hong Kong's de facto constitution.

"Freedom of expression, freedom of reporting are core values in Hong Kong, and as the Chief Executive, I ... will safeguard all these rights as enshrined in the Basic Law," Lam said. "Every act, every case will be dealt with in accordance with the law, the policy and the circumstances, including the facts of the case."

Freedom of expression has been looking increasingly shaky in recent weeks, however. On Wednesday, Chinese dissident writer Ma Jian, who is based in London, said that an event he was due to speak at in the city had been canceled by the venue.

Ma was scheduled to host two talks Saturday at Tai Kwun, an art space which has received government funding, as part of the events of the Hong Kong International Literary Festival. Part of the talk was to focus on his new book, "China Dream."

But on Wednesday night, Ma tweeted: "Just been told that my two events at the Hong Kong International Literary Festival this week can no longer be held at Tai Kwun, where all the other events are taking place. An alternative venue will have to be found. No reason has been given to me yet."

Just been told that my two events at the Hong Kong International Literary Festival this week can no longer be held at Tai Kwun, where all the other events are taking place. An alternative venue will have to be found. No reason has been given to me yet. https://t.co/wqJHs79JkW — 马建 Ma Jian (@majian53) November 7, 2018

I wouldn't use Tai Kwun as a platform to promote my 'political interests'. I'm a novelist, not an activist, and am attending the Festival to discuss my new novel, China Dream. My 'politics' are simple: I believe in free thought and free speech. Without them, life has no meaning. — 马建 Ma Jian (@majian53) November 8, 2018

In a statement Thursday, Director of Tai Kwun Timothy Calnin said organizers "do not want Tai Kwun to become a platform to promote the political interests of any individual."

"The cancellation appears to be at the very least an act of self-censorship, which would add to a growing list of incidents of suppression of free expression in Hong Kong," said Jason Y. Ng, president of PEN Hong Kong, a pro-free speech organization.

"It is all the more jarring that the decision was made by a publicly funded venue that claims to celebrate and support the arts and creativity," added Ng.

A second replacement venue which had stepped in to host the event has also pulled out, according to Hong Kong Free Press. There's no mention of the venue on the Hong Kong Literary Festival web page promoting the Ma Jian talk.

It is unclear whether Ma will be allowed entry in the city. Writing on Twitter Thursday, Ma said that he remained "determined to go" to the city despite concerns that he would be turned away by immigration officials on arrival. "It is precisely at times such as this when free speech is under threat that writers have a duty to speak out," he added.

Last week, another Chinese dissident decided against traveling to Hong Kong amid heightened safety fears.

Artist Badiucao had been due to present a new work at an event that was itself later canceled , following alleged threats made to the organizers.

Posters of Chinese President Xi Jinping by dissident artist Badiucao.

"We are sorry to announce that the exhibition 'Gongle,' by Chinese artist Badiucao, has been canceled," the Hong Kong Free Press, a local publication which was co-sponsoring the event, said in a statement.

"The decision follows threats made by the Chinese authorities relating to the artist. Whilst the organizers value freedom of expression, the safety of our partners remains a major concern."

Hong Kong police said that anyone with safety concerns should contact them, but would not comment on the individual case. Representatives of the Chinese government in Hong Kong also did not comment.

Taken together, Mallet, Ma and Badiucao's experiences have raised severe concerns about Hong Kong's ongoing commitment to freedom of expression and freedom of the press, both of which are enshrined in its de facto constitution but heavily limited in mainland China.

"To deny Mallet his work after hosting Andy Chan from the HKNP at the FCC and expelling him from Hong Kong was ridiculous enough, and a grave infringement of press freedom in itself," democracy activist Joshua Wong said Friday.

"Banning him from the city altogether, even as a tourist, is nothing less than an authoritarian attempt to censor all opposing voices. This development is extremely worrying, especially for journalists sent to this city to report on Hong Kong and Chinese political situations. I hope that the international community can now see the severity of the situation of freedom in Hong Kong, and try to protect the rights of their own citizens here," added Wong.