A Hong Kong court on Wednesday convicted prominent activist Agnes Chow of rallying in an unauthorized protest that saw thousands of protesters besieging the police headquarters amid a rising anti-government movement last year.

The West Kowloon Magistracy convicted Chow, 23, of taking part in and inciting others to join an unauthorized assembly on June 21 last year, where a crowd rallying at the legislature complex protesting against a proposed China extradition bill and police brutality against protesters in past demonstrations moved to blockade the nearby police headquarters.

Hong Kong pro-democracy activist Agnes Chow speaks after being convicted at West Kowloon Court on Aug. 5, 2020, of rallying in an unauthorized protest that saw thousands of protesters besieging the police headquarters amid a rising anti-government movement in 2019. (Kyodo)

"I am facing the trial in tranquility," Chow told reporters before standing in court. "Under the strong sense of fear of the national security law, it is even more important for us Hong Kongers to not surrender and to continue to believe in the universal values of democracy and freedom."

Chow, then a member of the now-disbanded activist group Demosisto, pleaded guilty to the allegations, the court heard. Mitigation and sentencing were scheduled for Dec. 1, pending the trial of two other former members of the group, activists Joshua Wong and Ivan Lam, on similar charges.

"Even the government try to prosecute us...it is still not the time for us to give up and surrender," Wong said after the pre-trial, as they were allowed to remain free on bail.

"Compared to the threat of the national security law, or being extradited to China or kidnapped by national security agents, the price we pay right now is just a small piece of cake. We will continue our fight to overcome the fear and threat," he said.

Wong, 23, charged with organizing, inciting and taking part in the unauthorized assembly, and Lam, 26, charged with incitement, will stand trial on Nov. 23.

In late June, the National People's Congress Standing Committee, China's top legislative body, enacted the security law prohibiting acts of secession, subversion, terrorism and collusion with foreign forces in Hong Kong.

A national security office run by Chinese officials was set up in Hong Kong. It can select cases to be investigated and prosecuted in mainland China.

Wong, who founded Demosisto, announced the disbanding of the group right before the law was promulgated, and said he will take up democracy advocacy in his personal capacity.