Pop singer and pro-democracy activist Denise Ho was arrested Wednesday at her home by Hong Kong's national security police. She was released on bail on Thursday.
Ho was one of seven people arrested during an operation targeting the pro-democracy online media group Stand News, according to The Guardian.
Police have accused Ho and the others of "conspiracy to publish seditious material," which CNN notes is a colonial-era crime.
The pop star, who was born in Hong Kong but was raised in Canada, has been an outspoken critic of the Chinese and Hong Kong governments, appearing both at the U.N. and in front of the U.S. Congress. She formerly served as a board member for Stand News.
In a Facebook post after her arrest, Ho wrote, "I am feeling OK. Friends who are concerned about me, please don't worry."
On Thursday, she tweeted she had been released from jail.
"Thank you friends for all your kind messages, I have been released on bail and have returned home safely," Ho wrote.
About 200 officers also raided the Stand News offices on Wednesday, The Guardian reports.
Stand News, a not-for-profit media outlet founded in 2014, announced its closure 10 hours after the raid. The Guardian reports that the national security department took boxes for evidence and froze almost $8 million in assets.
In response to Wednesday's arrests, U.S. Secretary of State Antony Blinken posted on Twitter, "A confident government that is unafraid of the truth embraces a free press. We call on the Hong Kong authorities to stop targeting the independent media and release those unjustly detained."
Ho's arrest is the first time such a renowned celebrity has been detained by authorities for a political crime after China's government in Beijing passed a national security law more than a year ago to quash pro-democracy protests in Hong Kong.
The pop singer is also one of the best-known out celebrities in the region, having come out as a lesbian around ten years ago. Ho became a central figure in the pro-democracy demonstrations shortly afterward.
"I have this younger generation who listens to my music," Ho told CNN in 2017. "So I think I have this responsibility to do the right thing, and not spread fear by my actions."
In 2019, during a speech to the U.N.'s Human Rights Council in Geneva, Ho called for the group to remove China from the council. She claimed China had violated promises it made when it took control of Hong Kong in 1997, a claim made by millions of protesting Hong Kong citizens at the time.
Mainland China has censored and blacklisted Ho for her activism, according to CNN. Chinese state media has previously called Ho "Hong Kong poison."