US President Donald Trump on Tuesday warned that Hong Kong could lose its status as a global financial centre if a proposed Chinese crackdown goes ahead, and promised a "very interesting" US response within days.
The Chinese legislation would ban secession, subversion, terrorism and foreign interference after months of massive, often-violent pro-democracy protests last year in the semi-autonomous territory. Hong Kong's chief executive, Carrie Lam, said on Tuesday that essential freedoms would remain.
But it is "hard to see how Hong Kong can remain a financial hub if China takes over", White House press secretary Kayleigh McEnany told a briefing, saying this warning came directly from Mr Trump.
"He's displeased with China's efforts," she said.
Mr Trump himself was asked later by reporters if he was considering sanctions against China or restrictions on visas for Chinese students. He said that was a "very important question" and that he would do something "you'll find very interesting".
"It's something you're going to be hearing about over the next, before the end of the week. Very powerfully, I think," he said, without giving more detail.
Critics fear the new law could be a death blow to Hong Kong's treasured liberties, which are crucial to making it an international financial center on a par with New York and London.
The announcement of plans for the law - which will be written by Beijing and bypass Hong Kong's legislature - sparked the biggest drop on the city's stock exchange in five years on Friday.
Ms Lam argued that the controversial law would "only target a handful of lawbreakers". However, she would not be drawn on what actions and opinions would be deemed illegal.
The commander of China's military garrison in Hong Kong warned the law would "punish any acts of separatism".
"Garrison officers have the determination, faith and capacity to defend national sovereignty," Chen Daoxiang told state-run CCTV.
But Ms Lam said fears the city's business-friendly freedoms were at risk were "totally groundless".
"Hong Kong's freedoms will be preserved and Hong Kong's vibrancy and the core values in terms of the rule of law, the independence of the judiciary, the various rights and freedoms enjoyed by people, will continue to be there," Ms Lam said.
The proposed law, she added, "only targets a handful of law-breakers... it protects the vast majority of law-abiding, peace-loving residents."