China's parliament approved national security legislation for Hong Kong on Thursday afternoon in Beijing.
While details about the bill remain scarce, the move will bypass Hong Kong's legislature, prompting concerns over eroding freedoms in the special administrative region.
The law is aimed at prohibiting secession, subversion of state power, terrorism activities and foreign interference. Details of the legislation have not been revealed.
Beijing has governed Hong Kong under the "one country, two systems" principle since the former British colony returned to Chinese rule in 1997. Before the transfer of sovereignty, the two sides signed a joint treaty, the Sino-British Joint Declaration registered at the United Nations, to guarantee a high degree of autonomy for Hong Kong, including a separate judiciary system, for 50 years after the handover.
The proposed national security law will bypass the regular lawmaking process in the Hong Kong legislature, raising concerns over whether it is a breach of Hong Kong's autonomy. There is fear the national security laws could lead to Chinese intelligence agencies setting up bases in Hong Kong and enforcing law directly.
Critics also say that Beijing may use the law to crack down on political opposition and free speech.
The Hong Kong Bar Association said there were "a number of worrying and problematic features" to the proposed law. It appears Beijing has no legal power to enact the law, the association added in a statement.
The Hong Kong legislature is obliged to craft and pass a national security law on its own under Article 23 of the Basic Law, the territory's mini constitution.
In 2003, a previous attempt to introduce national security legislation in Hong Kong was shelved after mass protests.
A Hong Kong official to China's National Congress told CNBC on Tuesday that Beijing is imposing the law on Hong Kong as the territory's legislature has simply failed to do it in the last 23 years since the transfer of sovereignty. Recent social unrest in Hong Kong also spurred China's decision to push on national security, he said.
Passing laws in Hong Kong requires the legislature to debate and vote on the proposed law. Often, there are public consultations.
This time, Beijing is likely to simply introduce its national security measures using Article 18 of the Basic Law. Under that clause, national laws to be applied to Hong Kong if they are under Annex III and related to defense, foreign affairs or "other matters outside the limits" of Hong Kong's autonomy.
The expected date is not yet known, but it is expected to be implemented in months, after details are drafted and passed by Beijing.
Reuters reported that the law will likely be in enacted ahead of Hong Kong's legislative elections in September.
This story has been updated to reflect that since the article's publication, Beijing has approved the national security bill for Hong Kong.