Hong Kong media tycoon Jimmy Lai has been denied bail while awaiting trial under a controversial new national security law.
Mr Lai, 73, is accused of conspiring with foreign forces to endanger national security, and could face a lengthy jail term.
He is the most high-profile person charged under the law.
Mr Lai founded the Apple Daily newspaper and is a fierce critic of the authorities in mainland China.
The tycoon was originally arrested under the law in August 2020 after a police raid on Apple Daily's head office. He was released on bail but then rearrested in December.
Hong Kong's court of final appeal ruled that a lower court was wrong to release Mr Lai briefly from detention.
However, the judges ruled that Mr Lai could make another bail application.
Previously, those accused of non-violent crimes in Hong Kong were routinely granted bail, but the new law removes that presumption.
China introduced the security law in the territory last year, saying it would ensure stability, but critics say it has silenced dissent.
Who is Jimmy Lai?
One of the city's most prominent supporters of the pro-democracy movement, Mr Lai is estimated to be worth more than $1bn (£766m). Having made his initial fortune in the clothing industry, he later ventured into media and founded Next Digital.
Next Digital publishes Apple Daily, a well-read tabloid which is frequently critical of Hong Kong and mainland Chinese leadership.
In a local media landscape increasingly fearful of Beijing, Mr Lai is a persistent thorn for China - both through his publications and writing.
It has seen him become a hero for many residents in Hong Kong but on the mainland he is viewed as a traitor who threatens Chinese national security.
Interviewed by the BBC before his arrest earlier in December, he said he would not give in to intimidation.
"If they can induce fear in you, that's the cheapest way to control you and the most effective way and they know it. The only way to defeat the way of intimidation is to face up to fear and don't let it frighten you."
What is in the National Security Law?
A former British colony, Hong Kong was handed back to China in 1997 but under the "one country, two systems" principle.
It was supposed to guarantee certain freedoms for the territory - including freedom of assembly and speech, an independent judiciary and some democratic rights - which mainland China does not have.
But the National Security Law has reduced Hong Kong's autonomy and made it easier to punish demonstrators.
The legislation introduced new crimes, including penalties of up to life in prison. Anyone found to have conspired with foreigners to provoke "hatred" of the Chinese government or the Hong Kong authorities may have committed a crime.
Trials can be held in secret and without a jury, and cases can be taken over by the mainland authorities. Mainland security personnel can legally operate in Hong Kong with impunity.
After the law was introduced, a number of pro-democracy groups disbanded out of fears for their safety.
The Chinese government defends the law, saying it will help return stability to the territory, which has been shaken by pro-democracy protests, and bring it more into line with the Chinese mainland.