He said he would direct his administration to "begin the process of eliminating policy exemptions that give Hong Kong different and special treatment" in its relations with the U.S. Trump said this would "affect the full range of agreements" between the U.S. and Hong Kong.
President Donald Trump has announced what he said are "significant actions" regarding USA relations with Hong Kong.
The People's Daily, one of the Chinese Communist Party's primary media outlets, also ran an editorial on Saturday, calling the USA move to end some trading privileges for Hong Kong "doomed to fail" and a "gross interference" in China's internal affairs.
"This is an emotional moment for Americans in Hong Kong and it will take companies and families a while to digest the ramifications", AmCham President Tara Joseph said in a statement.
More than 102,000 people in the U.S. have lost their lives to Covid-19 - by far the biggest death toll in the world.
The security legislation bans secession, subversion of state power, terrorism, foreign intervention and allows mainland China's state security agencies to operate in Hong Kong.
Rights groups have slammed the new Chinese law for Hong Kong, not only for its method of passage but also because it is seen as allowing mainland China to further target dissent within the city and quash anti-government protests that have shaken the territory throughout the past year.
"Whatever attempt at suppressing or intimidating Hong Kong officials there may be, I think it won't succeed, because we believe what we are doing is right", said John Lee, Hong Kong's secretary for security. Demonstrators are expected to take to the streets on Sunday. This can potentially pave the way for the US Congress revoking Hong Kong's special trade status which it enjoys under the US law.
Trump's comments concerning Hong Kong's autonomy come just a day after US Secretary of State Mike Pompeo made a similar assertion to Congress.
Meanwhile, the last British governor of Hong Kong, Chris Patten, said Chinese President Xi Jinping is risking a new Cold War with China's "thuggish" crackdown on the territory. The protests continued after Hong Kong's Legislative Council shelved the amendment.
It's not yet clear what impact the decision will have on USA companies that operate in Hong Kong, or on the city's position as Asia's major financial hub.
Meanwhile, Chinese Foreign Ministry spokesman Zhao Lijian has said that Mr Trump is trying to mislead the public, smear China and "shift the blame for [the US's] own incompetent response".
Trump said the United States will strip Hong Kong of the special policy measures on extradition, trade, travel and customs the U.S. had previously granted it. In the past decade, the United States trade surplus with Hong Kong has been the biggest among all its trading partners, totalling $297 billion from 2009 to 2018.
President Donald Trump has been criticised at home and overseas after announcing he is ending USA ties with the World Health Organization (WHO). They say such action is urgently needed after months of sometimes violent anti-government, anti-China protests rocked the city a year ago.
The Irish politician was similarly critical of Trump back in April, when the US President cut funding to World Health Organization, accusing them of mishandling the pandemic and covering up the initial outbreak in China.
The Republican party have been clamoring to throw out Chinese students enrolled in sensitive fields.
Mr Trump also faced pushback from public health experts, Democrats and even members of his own party, who said the withdrawal will deal a blow to worldwide cooperation precisely when it is most needed to counter the ongoing Covid-19 pandemic.