Hong Kong has refused to renew the work visa of a Financial Times journalist after he presided over a speech at the local foreign press club by a politician advocating independence from China for the former British colony.
The Financial Times, in an emailed statement to CNBC on Friday, said "no reason has been given for the rejection."
Victor Mallet, Asia news editor for the British-based, Japanese-owned paper, chaired the event in August at the Foreign Correspondents' Club of Hong Kong in his capacity as a vice president of the institution.
The speech on Aug. 14 by Andy Chan Ho-tin of the now-banned Hong Kong National Party and a question-and-answer session that followed drew condemnation from mainland Chinese and Hong Kong authorities, who had called for it to be canceled.
"This is the first time we have encountered this situation in Hong Kong," the Financial Times said.
The Hong Kong government in a statement said that it would not comment on individual cases.
"In handling each application, the Immigration Department acts in accordance with the laws and prevailing policies, and decides whether to approve or refuse the application after careful consideration of individual circumstances of each case," the statement said.
The FCC said it was expecting a full explanation from the Hong Kong authorities.
"In the absence of any reasonable explanation, the FCC calls on the Hong Kong authorities to rescind their decision," the club said in a statement late on Friday, describing the move as "extremely rare, if not unprecedented."
Britain handed back Hong Kong to China in 1997 but not before negotiating guarantees for the territory's autonomy, including the retention of its legal system and free speech protections.
But the central government in Beijing has drawn a red line at any independence advocacy. In an unprecedented move, Hong Kong authorities last month banned Chan's party as a security threat.
Analysts and human rights advocates have expressed concern in recent years over moves by Beijing that they say are eroding Hong Kong's autonomy under the "one country, two systems" framework that was supposed to remain unchanged for 50 years from 1997.
In the speech, Chan lashed out at China, calling it a "large empire" that was trying to eliminate Hong Kong's local identity. He said the city had been a British colony and was now a Chinese one.
Ahead of the speech, the city's Foreign Correspondents' Club issued a statement defending the need to hear different views and said that its invitations do not indicate endorsement or opposition of the the views of the speakers.
Reuters received multiple messages via email and social media from foreign banking and legal professionals expressing shock at the decision.
A spokesman for the U.S. Consulate General described the rejection as "deeply troubling."
"This decision is especially disturbing because it mirrors problems faced by international journalists in the mainland and appears inconsistent with the principles enshrined in the Basic Law," he said.
Reporters Without Borders called on Hong Kong authorities to reverse their decision.
"This is clearly a form of retaliation for his involvement in the public talk organised in August by FCCHK, which angered Beijing by featuring a pro-Hong Kong independence activist," the group said in a statement.
"Such action is yet another proof that the Chinese authorities are extending their policy of intimidating foreign journalists to the territory of Hong Kong," it said.
The Hong Kong Journalists Association (HKJA) said it was shocked at the move and urged the government to reconsider and explain its decision.
"If left unexplained, it will give rise to worries that it is an act of reprisal against Mr Mallet, further undermining public confidence in freedom of speech and the press," the HKJA said.
Twenty-two lawmakers from Hong Kong's democratic opposition called for Mallet's visa to be reissued.
"It is sending a very wrong message to the international community that Hong Kong is just another city in mainland China," veteran Democrat Party legislator James To told reporters.
Some pro-establishment politicians backed the government's move, however, saying strong messages had to be sent that Hong Kong had zero tolerance of independence calls, government-funded broadcaster RTHK reported.
New York-based Human Rights Watch said in a statement the visa rejection, together with the unprecedented banning of the Hong Kong National Party, showed a quickening downward spiral for human rights in Hong Kong.
"This is shocking and unprecedented," it said. "The Hong Kong authorities' visa renewal rejection — without explanation — of a journalist who's done nothing more than his job smacks of Beijing-style persecution of critics."
The FCC, whose members include senior lawyers, scholars and government officials besides journalists, has long portrayed itself as fostering and defending free speech.
Mallet has worked as a journalist and foreign correspondent for more than 30 years, first at Reuters and then for the Financial Times, including more than 12 years in Asia.
—CNBC's Paula Sailes and Vivian Kam, and Reuters contributed to this report.