Hong Kong Police Wanchai district headquarters File Photo:Xinhua

Four people who claimed to be students have been arrested for breaching the national security law for Hong Kong and suspected of secession by advocating for "Hong Kong independence," the Hong Kong Police Force (HKPF) announced on Wednesday night.

Hong Kong media reported that this is the first action taken by the new national security department under the police force since it was officially established in early July.

The four, three men and one woman aged between 16 and 21, were arrested at around 3:30 pm on Wednesday, Senior Superintendent Li Kwai-wah of the national security department under the HKPF announced at a press conference at 11 pm. 

It involved a group setting up an organization on a social platform advocating for "Hong Kong independence." The platform of the organization claimed to establish a "Hong Kong Republic." There was also a manifesto inciting others to join the group, Li said. 

If the crime is deemed as serious, they could be sentenced to 10 years in prison, and police can take DNA samples from the arrested individuals, Li said.

Li said he believed that the organization had been set up recently and that the message left on the social platform was only discovered after July 1 this year, and that inciting, aiding and abetting such an incident constituted sedition. 

The police force did not disclose the names of the arrested people and the organization, but Studentlocalism, a secessionist group, announced on its Facebook page on Wednesday night that Tony Chung Hon-lam, one of the former conveners of the organization, was "arrested for inciting secession," local media reported. 

On Sunday, the organization published an article on its Facebook page titled "Counterbalancing Chinese nationalism and constructing Hong Kong nationalism," with the hashtags including "independence is the only way for Hong Kong" and "Liberate Hong Kong, Revolution of Our Time."  

The government of the Hong Kong Special Administrative Region (HKSAR) said on July 2 that the slogan, "Liberate Hong Kong, Revolution of Our Time," has the implications of secessionism, alienating HKSAR from China, changing HKSAR's legal status or subverting the State power under the current circumstances.

Studentslocalism also announced it shut down its headquarters in Hong Kong on June 30, the same day the national security law for Hong Kong took effect, and said all the group's affairs would be handled by overseas members instead. 

They set up a division in the US on June 30, according to the group's Twitter.   

A Global Times reporter found that the group continued advocating "Hong Kong independence" on an overseas social media platform after June 30. In a post on Twitter on July 2 they said "disintegrate China."

According to Li Xiaobing, an expert on Hong Kong, Macao and Taiwan studies at Nankai University in Tianjin, whether the suspects are to be convicted under the national security law for Hong Kong depends on whether some of their speeches or activities after June 30 damage the interests protected under the national security law. 

According to Article 20 of the national security law for Hong Kong, a person who organizes, plans, commits or participates in any of the acts that separates the HKSAR from China, whether or not by force or threat of force, with a view to committing secession or undermining national unification shall be guilty of an offence, the principal offender shall be sentenced to life imprisonment or fixed-term imprisonment of not less than ten years. 

A person who actively participates in the offence shall be sentenced to fixed-term imprisonment of not less than three years but not more than ten years; and other participants shall be sentenced to fixed-term imprisonment of not more than three years, short-term detention or restriction.