• The closure of pro-democracy newspaper Apple Daily is a sign that press freedom is under threat in Hong Kong, said Ronson Chan, chairperson of Hong Kong Journalists Association.
• HKJA and seven other industry groups released a statement that blamed the end of Apple Daily — which had operated for 26 years — to "continuous government oppression."
• Apple Daily printed its last edition on Thursday, and its digital content was no longer accessible as of 11:59 pm local time Wednesday.

The closure of Hong Kong pro-democracy newspaper Apple Daily is a sign that press freedom is under threat in the semi-autonomous region, according to a representative of the Hong Kong Journalists Association.

"The threat is clear, very clear that we have to learn lessons from Apple Daily," Ronson Chan, chairperson of the Hong Kong Journalists Association, told CNBC's "Street Signs Asia" on Thursday.

The association and seven other industry groups released a statement that attributed the end of Apple Daily — which had operated for 26 years — to "continuous government oppression." Apple Daily printed its last edition on Thursday, and its digital content was no longer accessible as of 11:59 pm local time Wednesday.

Prior to the shutdown, Hong Kong authorities froze assets linked to Apple Daily — a move that left the newspaper with little resources to sustain operations. Around 500 police officers also raided the newspaper's offices last week and arrested several executives and staff for alleged violations of the national security law.

When asked about Apple Daily's alleged offenses, Hong Kong's Secretary for Security John Lee said last week that "we are talking about a conspiracy in which the suspects tried to make use of journalistic work to collude with a foreign country or external elements to impose sanction or take hostile activities against Hong Kong" and China.

Apple Daily had come under increasing pressure by Hong Kong authorities. Its owner, media tycoon Jimmy Lai, is a strong critic of the Chinese central government. He is now serving jail time after being arrested under the security law.

The national security law came into force last year. Beijing said the law is aimed at prohibiting secession, subversion of state power, terrorism activities and foreign interference.

Chan, who is also deputy assignment editor at online news site The Stand News, said it's concerning that the law's red lines are not clear. That means independent journalists "have to bear some risks" in order to do their job, he added.

Hong Kong authorities' use of the national security law has been criticized by some including the governments of the U.S. and U.K.

Following Apple Daily's closure, British Foreign Secretary Dominic Raab said in a statement that "it is crystal clear that the powers under the National Security Law are being used as a tool to curtail freedoms and punish dissent — rather than keep public order."

Meanwhile, a European Union spokesperson said Apple Daily's closing "seriously undermines media freedom and pluralism" in Hong Kong.