A top Hong Kong media executive said Thursday that HSBC had frozen his account after he and others from his pro-democracy newspaper were arrested under a new national security law Beijing imposed on the city.

Cheung Kim-hung, chief executive officer of Next Digital Limited, told the group's flagship newspaper Apple Daily that he could not withdraw or transfer money from his personal HSBC account, although his credit card was still working.

"The bank did not notify me," Cheung said. "I found some functions were unusable only when I wanted to use them."

His revelation came a day after US Secretary of State Mike Pompeo blasted the British bank for maintaining accounts of officials Washington has sanctioned for curtailing the freedoms of Hong Kongers, while freezing the accounts of those seeking freedom.

"The United States is dismayed to learn the Chinese Communist Party continues to bully our British friends and their corporate leaders," Pompeo wrote in his tweet, an apparent reference to the pressure Hong Kong-based banks have been put under by Beijing.

Pompeo was retweeted by Jimmy Lai, the owner of Apple Daily and a fierce critic of Beijing, who was arrested alongside Cheung.

Lai aide Mark Simon told the South China Morning Post that HSBC had frozen the media tycoon's personal and credit card accounts, although Next Digital's business accounts remained active.

Cheung said the freeze came after August 10, when around 200 police officers raided the newsroom of Apple Daily, which is unapologetically pro-democracy, and arrested 10 executives.

HSBC is a Hong Kong institution despite now being headquartered in Britain
HSBC is a Hong Kong institution despite now being headquartered in Britain AFP / Laurel Chor

Six of those arrested -- including Lai and prominent activist Agnes Chow -- were accused of "collusion with foreign forces", a newly created national security offence.

International banks in Hong Kong are caught in the crossfire between the United States and China as the superpowers clash over the city's future.

US President Donald Trump has signed a bipartisan bill sanctioning Chinese and Hong Kong officials responsible for the current crackdown on political freedoms in the city.

But China's new security law also bans Hong Kong businesses from complying with foreign sanctions.

Banks such HSBC are taking flak from both sides.

Politicians in the US and Britain have castigated the British bank for supporting the national security law in Hong Kong.

China's state media, meanwhile, have accused the bank of helping US prosecutors build a case against Huawei executive Meng Wanzhou for allegedly breaching Iran sanctions.

The bank published a rebuttal on its Chinese Weibo account, which was quickly censored.