Police arrest the group for seditious social media posts under the much criticised law.

Hong Kong’s national security police have arrested six people accused of publishing seditious social media posts.

The charges, announced by the police in a statement on Tuesday, are the first to be publicly laid under the city’s much criticised national security law.

In the statement, the police said that among those arrested was a woman who, with the help of five others, had used a social media page to anonymously publish the posts starting in April.

“[They] provoke hatred against the central government, the Hong Kong government and the city’s judicial institutions, and aim to incite netizens to organise or participate in illegal activities during a later period,” the police statement said.

The statement did not reveal details regarding the social media page or the content of the posts and did not identify the six people, aged 37 to 65.

However, local media identified the woman as Chow Hang-tung, a prominent barrister and pro-democracy activist who is in jail on other charges.

Hong Kong’s new national security law came into force in March after pro-Beijing lawmakers passed it unanimously.

It allows life imprisonment for residents who “endanger national security”, deepening worries about an erosion of the city’s freedoms four years after Beijing imposed a similar law that all but wiped out public dissent.

Locally known as Article 23, the new law has expanded the government’s power to deal with future challenges to its rule.

It focuses on five types of crime: treason, insurrection, sabotage that endangers national security, external interference in Hong Kong’s affairs, and espionage and theft of state secrets.

The law expands the government’s ability to close down civil society organisations and prosecute residents for offences like collaborating with foreign forces to influence legislation or publishing “misleading statements”. It is also designed to jail people who damage public infrastructure.

Some of its provisions threaten criminal prosecutions for acts committed anywhere in the world.