Two Hong Kong pro-democracy activists pleaded guilty on Tuesday to organizing or participating in an illegal assembly during anti-government protests in 2019.

Au Nok-hin and Leung Yiu-chung are both former members of the Hong Kong legislature. They are among nine prominent activists who were arrested in April last year, in what was seen as a move to crack down on dissent.

Seven others, including media tycoon Jimmy Lai, pleaded not guilty. Tuesday's trial is expected to last for 10 days.

Au had been charged with both organizing and participating in an illegal assembly and

Leung was charged with participating in an illegal assembly.

Among the nine defendants who pleaded not guilty are Martin Lee, an 82-year-old barrister who was once chosen by Beijing to help write Hong Kong's mini-constitution, and Margaret Ng, a 73-year-old barrister and former opposition lawmaker.

'Deterioration of the rule of law'

Before the trial, supporters and several of the accused rallied outside the court. One banner read "Peaceful Assembly is Not a Crime; Shame on Political Prosecution."

Lee Cheuk-yan, one of the nine defendants, said the law has been unfairly used to quash dissent. "It is very sad to witness the deterioration of the rule of law in Hong Kong into a rule by fear," he said. 

Some of the defendants are also leading members of the Civil Human Rights Front (CHRF), the coalition that organized a series of major rallies in 2019. 

The group is being prosecuted for organizing an unauthorized assembly on August 18, 2019, in one of the largest that took place in Hong Kong, as demonstrators hit the streets for seven straight months to call for democracy and greater police accountability. Organizers estimated that 1.7 million people showed up. 

In their opening statement, prosecutors accused the activists of defying police instructions that day and encouraging crowds to march across Hong Kong's main island. 

Since 2019, protests have been all but outlawed with authorities either refusing permission on security grounds or later because of the pandemic.

Mainland China has also since implemented a new security law, which criminalizes some forms of dissent.

lc/rt (Reuters, AP, AFP)