Activist Andy Li Yu-hin appeared before a Hong Kong court Wednesday for the first time since serving a jail term on the mainland for attempting to flee protest-related charges last summer.

Chinese authorities released the 30-year-old March 23 and he spent two weeks in pandemic quarantine at a psychiatric hospital, according to reports, before being remanded in police custody.

Li's journey through the Hong Kong and mainland legal systems has been confusing.

Upon his return, authorities charged Li under the national security law with collusion, conspiracy to assist an offender and possession of ammunition without a license over his attempted escape to Taiwan in August.

The activist was represented at this first hearing by a lawyer not known to Li's family. Barrister Lawrence Law, twice suspended from practicing in Hong Kong over misconduct, refused to disclose who had hired him but issued a statement last week saying he had not been appointed by the authorities.

Li is one of 12 people who attempted to flee prison sentences for their roles in the anti-establishment riots of 2019. But while on route to Taiwan in a small motor boat in August, the group was apprehended by a China coast guard vessel and the fugitives were charged with crossing the border illegally.

Eight of these pro-democracy fugitives completed their China prison terms in March and have returned to Hong Kong to face original charges. But another four members of the "Hong Kong 12" remain behind bars on the mainland. It is not known when they will be freed.

During his Wednesday court appearance, Li did not seek bail. He will remain in police custody until his next hearing May 18.

Meanwhile in another Hong Kong courtroom, three prominent pro-democracy figures pleaded guilty to charges relating to a rally two years ago.

"It is meaningless to continue our legal challenge...We've lost that case but will continue with appeals to regain our rights," Labor Party leader Lee Cheuk-yan said Wednesday after pleading guilty alongside publisher Jimmy Lai and lawmaker Yeung Sum to unauthorized assembly at a protest in August 2019.

The trio could face up to five years in prison, and their admission of guilt follows the conviction of seven, including Lai, over another illegal rally in 2019.