HONG KONG — The Hong Kong police on Thursday launched a sweeping clampdown on Apple Daily, an embattled pro-democracy newspaper, arresting five senior executives, freezing company accounts and warning its readers not to repost some of the publication’s articles online.
It was not immediately clear how the clampdown would affect Apple Daily’s ability to publish. But the police raid and the new restrictions represent the most aggressive use yet of Hong Kong’s sweeping national security law, imposed last year by Beijing, against a media outlet. It will likely have a chilling effect on other media in Hong Kong, a former British colony once known for its vibrant newspaper scene and broad free speech protections.
The police said that they had arrested five executives at Apple Daily and its parent company, Next Digital, on suspicion of “collusion with a foreign country or with external elements to endanger national security.”
Apple Daily’s editor in chief, Ryan Law, was among those arrested. Trading of Next Digital’s shares were suspended in Hong Kong on Thursday morning following news of the arrests.
Footage broadcast by Apple Daily reporters showed a few hundred police officers entering the headquarters of Next Digital. Some carted away suitcases. A photo posted by Apple Daily on its Instagram account showed officers looking through files on journalists’ computers.
The police said that a search warrant had authorized “the power of searching and seizure of journalistic materials.”
Employees of Next Digital faced steep police scrutiny. The authorities set up makeshift posts at the building entrance, requiring employees to register personal details. The officers restricted employee access to certain floors of the building and warned them to turn off their cameras.
Police said they were prompted to act after an investigation showed more than 30 Apple Daily articles called on foreign countries to enact sanctions against Hong Kong and China. The United States has imposed sanctions against some Hong Kong and Chinese officials and imposed other restrictions after Beijing tightened its grip over the city.
“We have very strong evidence that the questionable articles play a crucial part in the entire conspiracy scheme, providing talking points to foreign countries or overseas institutions to impose sanctions,” Li Kwai-wah, a senior superintendent in the police national security department, said at a news conference.
Referring to the detained executives and editors, Mr. Lie added: “There’s absolutely no shirking of responsibility for the contents of the articles, their style and guiding principles.”
Mr. Li also warned the public against sharing articles from Apple Daily. “As a law enforcer, I would advise you not to invite suspicion,” he said. He did not specify which articles.
The authorities had already been putting pressure on Apple Daily and its owner. Next Digital’s founder, Jimmy Lai, is serving a prison sentence for illegal assembly. He is facing separate charges under the national security law, with prosecutors accusing him of calling for international sanctions against Hong Kong. The police raided Next Digital’s headquarters last year.
But the police’s focus on Apple Daily’s content marked a sharp escalation, Thomas E. Kellogg, executive director of the Georgetown Center for Asian Law, said in an email.
“It seems clear that the Hong Kong government is determined to bring down Apple Daily, as one of the most outspoken media outlets in Hong Kong,” he said, calling the targeting of the newspaper for its journalism “a deeply troubling development.”
In addition to Mr. Law, the arrested executives included Next’s chief executive, Cheung Kim-hung, and Tat Kuen-chow, its executive director. Among the paper’s editors, they included Cheung Chi-wai, its chief executive editor, and Chan Puiman, deputy chief editor.
The authorities froze about $2.3 million in accounts belonging to Apple Daily and affiliated companies Apple Daily Printing and AD Internet.
Mr. Lai and his newspaper have long been a thorn in the side of the Chinese and Hong Kong governments, and Beijing has targeted him as one of its leading enemies in the territory.
Hong Kong’s chief of police, Chris Tang, singled out Apple Daily in April for its coverage of a national security event hosted by the police and warned that the authorities would investigate news outlets seen as having endangered national security.
In the year since the national security law went into effect, the police have arrested 112 people in national security investigations, and 57 have been charged under it.