Four people, three males and one female between 16 and 21 years old claiming to be students, were arrested on suspicion of violating Article 20 and Article 21 of the Law of the People's Republic of China on Safeguarding National Security in the Hong Kong Special Administrative Region (HKSAR), Senior Superintendent Li Kwai-wah confirmed.

The arrests were made on Wednesday afternoon. Police also seized cellphones, computers and files as evidence. 

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Intelligence and investigation showed that a group recently announced on social media the establishment of an organization advocating "Hong Kong independence," and incited others to join them, Li  added. 

This is the first law enforcement operation launched by the National Security Department of the Hong Kong Police Force in accordance with the national security law for Hong Kong, which clearly defines offenses endangering national security, the Hong Kong police pointed out, urging people not to defy the law and emphasizing that those who commit relevant crimes online will also be held liable. 

The police did not disclose the identity of the arrested. Local media said one of them is Tony Chung Hon-lam, the former convener of a separatist student group.

Under Article 20, anyone who organizes, plans, commits or participates in any act, whether or not by force or threat of force, with a view to committing secession or undermining national unity is guilty of violating the security law. The maximum penalty for such a violation is life imprisonment. Article 21 stipulates that one who incites, assists in, abets or provides financial help or property to other people committing an offense under Article 20 are in violation of the law, punishable by imprisonment of five to 10 years.

(With input from Xinhua)