Beijing has rejected the international backlash, accusing critics of "smearing" the Chinese city's judicial system.

Press advocates say the trial highlights dying press freedoms under a national security law imposed by Beijing following huge and at times violent pro-democracy protests in 2019.

Diplomats from the United States and the European Union were among those watching as the verdicts were pronounced, with Matthias Kaufmann, deputy head of the EU mission, saying he came to the court "to signal close interest in these cases".

- Britain: 'targeted' -

London said Lai, a British citizen, "has been targeted by the Chinese and Hong Kong governments for peacefully exercising his right to freedom of expression".

"We will continue to appeal to the Chinese government ahead of Jimmy Lai sentencing for his release and access to medical treatment," the office of Prime Minister Keir Starmer said.

- China: 'punishing criminal acts' -

Chinese foreign ministry spokesman Guo Jiakun said Beijing "firmly supports" Hong Kong in "punishing criminal acts that endanger national security".

"China expresses strong dissatisfaction and firm opposition to the brazen defamation and smearing of the judicial system in Hong Kong by certain countries," he said.

- Australia: 'deeply concerned' -

The Australian government said it was "deeply concerned by the guilty verdict".

"We have been clear in expressing our strong objections to Hong Kong authorities on the continuing broad application of national security legislation to arrest and pressure pro-democracy figures, opposition groups, media, trade unions and civil society," the foreign ministry said.

- Taiwan: 'profound sorrow' -

Taipei decried Lai's detention as a "violation of justice" and said his conviction has caused "profound sorrow and deep disappointment in Taiwan".

"This ruling sends a message to the world that Hong Kong's freedom, democracy and judicial independence have been steadily eroded," Taiwan's Mainland Affairs Council said.

- European Union: 'politically motivated' -

The European Union said it "deplores" Lai's conviction and called for his release.

"This prosecution is politically motivated and emblematic of the erosion of democracy and fundamental freedoms in Hong Kong since the imposition of the National Security Law," the bloc said.

- Amnesty: 'death knell for press freedom' -

"The conviction of Jimmy Lai feels like the death knell for press freedom in Hong Kong, where the essential work of journalism has been rebranded as a crime," rights group Amnesty International said.

"Lai has been jailed simply because he and his Apple Daily newspaper criticised the government."

- Reporters Without Borders: 'trumped-up' -

Reporters Without Borders expressed outrage at the verdict, calling the charges "trumped-up".

"It is not an individual who has been on trial -- it is press freedom itself, and with this verdict that has been shattered," the advocacy group said.

- Committee to Protect Journalists: 'disgraceful' -

The Committee to Protect Journalists called the verdict a "disgraceful act of persecution".

"The ruling underscores Hong Kong's utter contempt for press freedom, which is supposed to be protected under the city's mini-constitution, the Basic Law," said the organisation's Asia-Pacific director, Beh Lih Yi.

- Hong Kong Journalists Association: 'irreversible damage' -

The Hong Kong Journalists Association said the trial has long "caused irreversible damage to Hong Kong's press".

It described a media climate of self-censorship and fear "to the point where even those in power cannot accurately assess public sentiment through news".