Hong Kong authorities on Wednesday arrested four individuals under a new security law for running a pro-independence group that called for making the city-state a republic, The South China Morning Post reported. The activists, aged between 16 and 21, were arrested from Yuen Long, Sha Tin and Tuen Mun areas of Hong Kong, but their identities were not revealed.

However, images posted on social media showed police taking away Tony Chung Hon-lam, one of the former convenors of Studentlocalism, in Yuen Long. Studentlocalism was a pro-independence group disbanded on June 30, hours before a new China-imposed law that criminalises “subversion, secession and collusion with foreign forces”, as well as terrorism, came into force.

National Security Department Senior Superintendent of Police Steve Li Kwai-wah said at a late evening press conference that a group formed by the accused had recently declared the establishment of a body to promote pro-independence politics, using “any means possible”, and to build a “Republic of Hong Kong”. The group is known as the Initiative Independence Party and operates on social media.

The group raised the matter of Chung’s arrest on its Facebook page. It also said that three men and one woman were among those arrested, and that a local court had refused them bail.

In a declaration posted on July 21, the group had said it was founded by former Studentlocalism members who were abroad and had finished their studies. “Before we triumph in building our nation that belongs to us Hong Kong nationals, Initiative Independence Party will forever fight alongside the entirety of Hong Kong nationals for our common dream,” the declaration proclaimed.

Li claimed the group had said that it would attempt to unite all pro-independence organisations in the city-state. Li said their claims might have breached Articles 20 and 21 of the new security law, which prohibit acts of organising, planning, committing or participating in altering the legal status of Hong Kong.

On July 4, motorcyclist Tong Ying-kit, 23, became the first person to be officially charged under the new security law, on one count of inciting secession and another of terrorism. Tong was arrested after allegedly riding into a group of policemen at a protest, carrying a flag and calling for the liberation of Hong Kong from Chinese rule. Tong fractured his leg in the incident.

The new security law

In June, China’s rubber-stamp Parliament, the National People’s Congress, passed a national security legislation for Hong Kong that would override local laws and give sweeping powers to security agencies. The unprecedented law is aimed at curbing protests – which rocked Hong Kong last year – and prohibiting subversion, separatism, “acts of foreign interference”, and terrorism. The new law will also allow China’s security personnel to operate in Hong Kong.

Under the new law, certain political views and symbols, including those showing support for the independence of Hong Kong, Taiwan, Xinjiang and Tibet from China, are now illegal. Officials in Hong Kong and Beijing have said the law is vital to plug gaps in national security exposed by the protests.

Four countries – New Zealand, Australia, Canada and the United Kingdom – suspended their extradition treaties with Hong Kong earlier this month, in moves to oppose the law.