Hong Kong media tycoon Jimmy Lai Chee-ying and nine other activists pleaded guilty on Monday to organizing an unauthorized assembly on Oct 1, 2019.

The 10 defendants include former lawmakers of the special administrative region and veteran activists Albert Ho Chun-yan, Lee Cheuk-yan, Leung Kwok-hung and convener of the Civil Human Rights Front－an organization that initiated major protests during the city's 2019 social unrest－Figo Chan Ho-wun.

The unauthorized assembly on China's National Day two years ago descended into violence between radical anti-government protesters and police. Some rioters threw gasoline bombs and sprayed corrosive liquid at the police and set fires on the streets.

In court, Chan, Ho, Lee and Leung also admitted guilt in a further offense associated with inciting others to join in an unlawful assembly on Sept 30, 2019.

Under the Public Order Ordinance, any person who organizes an unauthorized assembly or attempts to direct others to take part in it has committed a crime that is punishable by imprisonment of up to five years.

Judge Amanda Woodcock, who is presiding over the case, will hear defendants' mitigation plea on May 24 and pass sentence on May 28.

Before the hearing, the Hong Kong Stock Exchange suspended trading in shares of Next Digital Ltd, after the Security Bureau of Hong Kong announced on Friday it was freezing the assets of Jimmy Lai, the company's founder and major shareholder.

Lai's assets were frozen in accordance with the city's National Security Law. Article 43 (Implementation Rules) of the law stipulates that "relevant persons and organizations must not, directly or indirectly, deal with certain property which is reasonably suspected to be related to offenses endangering national security".

Lai now faces three charges under the National Security Law for Hong Kong, including colluding with a foreign country or external elements to endanger national security. He is currently serving a 14-month prison sentence he received in April for taking part in unauthorized assemblies in August 2019.

Next Digital disclosed in a statement that the trading in its shares will remain halted before an announcement is released in relation to the freeze on Lai's assets and shareholdings in the company.