HONG KONG - Hong Kong media tycoon and pro-democracy activist Jimmy Lai was denied bail on Thursday on a charge of fraud related to the lease of a building that houses his Apple Daily, an anti-government tabloid.

Hong Kong authorities have intensified a crackdown on key opposition figures since Beijing circumvented the territory's legislature and imposed sweeping national security legislation on the global financial centre on June 30.

While Lai's fraud charge did not fall under the national security law, it marks the latest crackdown on pro-democracy figures in the former British colony, which was handed back to Beijing in 1997 with a promise of keeping its free-wheeling way of life for 50 years.

Critics say the law crushes freedoms enshrined under the "one country, two systems" formula, while supporters say it will bring stability after prolonged anti-China, pro-democracy protests last year.

Lai, an ardent critic of Beijing, was detained on Wednesday and the case has been adjourned until April, according to media.

On Wednesday, one of Hong Kong's most prominent democracy activists, Joshua Wong, was jailed for more than 13 months for his role in an anti-government rally in 2019, the toughest and most high-profile sentencing of an opposition figure this year.

Wong's long-time colleagues Agnes Chow, 23, and Ivan Lam, 26, were jailed for a total of 10 and seven months, respectively.

U.S. Secretary of State Mike Pompeo said Washington was "appalled" by the persecution of Hong Kong’s pro-democracy advocates.

"We stand with Joshua Wong, Agnes Chow, Ivan Lam, Jimmy Lai, the people of Hong Kong, and all the people of China," he said in a statement.

"The use of courts to silence peaceful dissent is a hallmark of authoritarian regimes and underscores once again that the Chinese Communist Party’s greatest fear is the free speech and free thinking of its own people."

Lai, 73, and two senior executives of his company Next Digital, were charged on Wednesday on suspicion of concealing from and falsely representing the use of their office to their landlord, a public corporation set up by the Hong Kong government.

The charge stated they were not using the office space as permitted under the lease between 2016 to 2020, and had sub-let part of the premises, resulting in benefits to Apple Daily.

Reuters was not able to reach Lai or his lawyers for comment.

Next Digital, which suspended trading on Thursday morning, said in a statement it did not expect the charges to have an immediate impact on daily operations, as the company is operated by a team of management personnel. Its shares will resume trading on Friday.

"This is about dirtying Jimmy up. It's Beijing's policing brought to Hong Kong," Mark Simon, an associate of Lai, told Reuters.

Lai was arrested in August when about 200 police officers swooped on his offices. Hong Kong police later said they had arrested nine men and one woman for suspected offences including "collusion with a foreign country/external elements to endanger national security, conspiracy to defraud" and others.

Suspicion of colluding with foreign forces carries a maximum sentence of life in jail under the new security law.

Lai has been a frequent visitor to Washington, where he has met officials, including Pompeo, to rally support for Hong Kong democracy, prompting Beijing to label him a "traitor". REUTERS