Hong Kong’s leader on Tuesday refused to say why the city denied a visa to a Financial Times journalist despite escalating demands for an explanation of the unprecedented challenge to freedom of the press.

Victor Mallet, the Financial Times’ Asia news editor and a British national, angered authorities in Beijing and Hong Kong by hosting a speech at the city’s press club by Andy Chan, the leader of a tiny pro-independence political party, in August.

Zhang Xiaoming, head of Beijing’s Hong Kong and Macau Affairs Office, told reporters at the time the press club had broken the law by hosting a “separatist”.

Chan’s party was later banned as Beijing cracks down on any pro-independence sentiment in the semi-autonomous city.

An application to renew Mallet’s work visa has been refused and on Sunday he was given seven days to leave Hong Kong.

Facing questions for the first time since the visa denial emerged last week, Chief Executive Carrie Lam, who is appointed by a pro-Beijing committee, said the decision had been handed down by immigration authorities.

She said linking it to the Chan talk was “pure speculation”.

But she declined to explain why Mallet has been effectively forced to leave the city. She reiterated comments by other senior Hong Kong officials that authorities would not comment on an individual visa, and the decision was made in accordance with the law.

‘One country, two systems’

Hong Kong, a former British colony, reverted to Chinese rule in 1997 amid guarantees the global financial hub would enjoy a high degree of autonomy and freedoms under a “one country, two systems” formula.

Critics say Hong Kong’s rights landscape has deteriorated in recent years amid a spate of controversies, including the jailing of young activists and disqualifications of pro-democracy members of the legislature.

Lam would not offer specifics on whether other journalists would face repercussions for reporting on the topic of independence, or speaking with independence activists.

“I’m sorry, I cannot tell you exactly how journalists should say, or act, or interview, but I can assure you … freedom of expression, freedom of reporting, are core values in Hong Kong.”

Mallet, who is in Hong Kong on a tourist visa that expires on Sunday, thanked all those supported him, including journalists, lawyers and citizens.

An online petition calling for authorities to reverse their decision and allow the seasoned journalist to work in the city again has drawn more than 10,000 signatures.

“I am very grateful to all those who have signed this petition, particularly those from Hong Kong, which has been home to our family for a total of more than seven years,” he wrote on Facebook.

Hong Kong enjoys rights unseen on the mainland, including freedom of speech and the press, which are enshrined in an agreement made when the city was handed back to China by Britain.

There are growing fears those rights are disappearing. Beijing regularly denies visas to foreign journalists, but it has not been a tactic used in Hong Kong.