At least 24 people in Hong Kong have been charged with taking part in a banned candlelight vigil on 4 June to mark the anniversary of China's 1989 Tiananmen crackdown.
Pro-democracy activist Joshua Wong was among those charged with "taking part in an unauthorised assembly".
Hong Kong has long been the only place on Chinese soil where a commemoration of the crackdown is allowed.
But it was banned this year, with authorities citing coronavirus fears.
It came weeks before a controversial national security law came into force, criminalising acts of anti-Beijing protest which could see Hong Kong residents sent to mainland China for trial.
It's led to fears that the territory's freedoms are being eroded. Critics had earlier said that it could led to pro-democracy protesters in the region being given life sentences.
What charges do they face?
Hong Kong police said in a statement that 24 people - 19 men and five women between the ages of 23-69 - had been charged with holding and knowingly taking part in an unauthorised assembly.
This charge existed before the national security law came into force on 30 June.
Mr Wong and at least six other activists including Nathan Law - who has since left for London - have been charged. Some of those charged are already facing charges of incitement over the vigil.
Media tycoon Jimmy Lai, a frequent critic of Chinese leadership, has also been charged.
"Clearly, the regime plans to stage another crackdown on the city's activists by all means," Mr Wong, who is also facing charges for another protest, said on Facebook.
"As our voices might not be heard soon, we hope the world can continue speaking up for the city's liberty and human rights."
All those charged are expected to appear in court on 15 September.
What was the Tiananmen Square crackdown?
On 4 June 1989, troops and tanks opened fire on pro-democracy protesters in Beijing - estimates of the dead vary from a few hundred to several thousand.
Hong Kong and Macau are the only parts of China that have been allowed to mark the day. In mainland China, authorities ban even oblique references the events of 4 June.
This year, Hong Kong authorities banned the vigil for the first time in 30 years, citing coronavirus measures.
Under Hong Kong's rules then, only groups of eight people were allowed to gather.
But on 4 June, thousands of protesters defied this ban and went ahead to stage a mass vigil anyway. Others joined in remotely.
One attendee said she was afraid it would be the last time Hong Kong could have a ceremony.
"We are afraid this will be the last time we can have a ceremony," Brenda Hui had said.
"But Hong Kongers will always remember what happened on June 4."