Hong Kong police said on late Wednesday that they had arrested four people on suspicion of breach of the national security law in the Hong Kong Special Administrative Region (HKSAR).

The National Security Department of the Hong Kong Police Force arrested three males and one female on Wednesday afternoon in different districts including Yuen Long, Tuen Mun and Sha Tin, Li Kwai-wah, senior superintendent of the National Security Department told a media briefing Wednesday night.

The four people, aged between 16 and 21 and claiming to be students, were arrested on suspicion of violating Article 20 and 21 of the Law of the People's Republic of China on Safeguarding National Security in the HKSAR, Li said.

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, he 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 in Hong Kong.

The national security law in Hong Kong clearly defines offences 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 student organization advocating "Hong Kong independence."