Several demonstrators who were apprehended for publicly protesting China's then-ongoing zero-COVID policy remain in detention, face charges or have not been heard from, Human Rights Watch said in a report on Thursday.
In late November, protests broke out in numerous cities across China calling for an end to the country's nearly three years of strict enforcement of the zero-COVID policy. Many demonstrators held up blank sheets of white paper, which became a symbol of their discontent.
Some protestors also shouted slogans calling for the ouster of President Xi Jinping or the ruling Communist Party.
The protests, unprecedented in Xi's decade in power, which has seen an increasingly heavy crackdown on dissent, petered out within days amid a heavy police presence. Numerous individuals were apprehended and subsequently released, protesters, lawyers and academics told Reuters at the time, adding that they were concerned that some could face consequences later.
Human Rights Watch researchers cited four protestors in Beijing - editor Cao Zhixin, accountant Li Yuanjing, teacher Zhai Dengrui, and journalist Li Siqi - as having been formally arrested for "picking quarrels and provoking trouble", which can carry a sentence of up to five years.
In Shanghai, the whereabouts of two protestors who demonstrated on Wulumuqi Road, Li Yi and Chen Jialin, are unknown, Human Rights Watch said.
The group called on authorities to release all of the individuals immediately.
Reuters could not independently verify the status of the individuals named in the report.
Calls by Reuters to China's Ministry of Public Security for a comment were not answered.
Human Rights Watch said "a few" protestors were released on bail.
"More protestors are believed to have been detained or forcibly disappeared, though their cases are not publicly known, given the Chinese authorities' practice of threatening detainees' families to keep silent," it said.
In early December, soon after the protests, China abruptly dropped most of its zero-COVID curbs, and the coronavirus has spread rapidly across the country.
(Reporting by Josh Horwitz; Editing by Tony Munroe and Christian Schmollinger)
