Hong Kong media tycoon Jimmy Lai was denied bail by the city's top court on Tuesday.
He's a prominent critic of Beijing and is the most high-profile person to be charged under Hong Kong's national security law.
Lai was detained in early December, then released on bail for about a week before he was brought back into custody for another hearing at the end of last year.
The court pointed to an article in the national security law, which says that bail won't be given unless "the judge has sufficient grounds for believing that [they] will not continue to commit acts endangering national security."
Beijing imposed the sweeping national security law last summer to punish anything China considers subversive with up to life in prison.
Critics say it is aimed at crushing dissent and it erodes freedoms in the semi-autonomous, Chinese-ruled city.
Its supporters say it restores stability after months of unrest during the city's anti-government protests in 2019.
When Lai was arrested under the law last year, nearly 200 police officers raided the newsroom of his Apple Daily newspaper.
Prosecutors say Lai illegally requested foreign intervention in statements he made last summer.
The tycoon has been a frequent visitor to Washington, D.C., meeting with the likes of former U.S. Secretary of State Mike Pompeo to rally support for Hong Kong democracy.