China promised Thursday to take countermeasures against Britain if it presses ahead with plans to extend citizenship rights to Hong Kongers after Beijing imposed a sweeping security law on the restless financial hub.
Beijing has faced a groundswell of criticism from primarily Western nations over its decision to impose a new law outlawing acts of subversion, secession, terrorism and colluding with foreign forces.
Hong Kong police fired water cannon and tear gas and arrested more than 300 people as protesters took to the streets in defiance of the sweeping security legislation introduced by China to snuff out dissent.
Early in the morning of July 2, Hong Kong police arrested a 24-year-old man at the city's airport on suspicion of attacking and wounding an officer during protests against a new national security law Beijing imposed on the financial hub.
On Wednesday, police posted pictures on Twitter of an officer with a bleeding arm saying he was stabbed by "rioters holding sharp objects". The suspects fled while bystanders offered no help, police said.
A police spokesman told Reuters the arrested man was surnamed Wong but could not confirm if he was leaving Hong Kong or working at the airport.
Local newspaper Apple Daily, citing unnamed sources, said the suspect was onboard a Cathay Pacific flight to London due to depart just before midnight.
A witness said "around 10 minutes before take-off, three police vehicles drove towards No 64 gate, outside the Cathay Pacific plane" and around 10 riot police ran up the bridge to the aircraft.
Cathay Pacific did not immediately respond to a request for comment.
Adding to concerns of Beijing's crackdown, Hong Kong's influential Bar Association published a new legal analysis warning that the wording of the law - which was kept secret until Tuesday - undermines the city's independent judiciary and stifles freedoms.
Britain has said the law breaches China's pre-handover "One Country, Two Systems" promise to grant residents key liberties - as well as judicial and legislative autonomy - until 2047.
It has responded by announcing plans to allow millions of Hong Kongers with British National Overseas status to relocate with their families and eventually apply for citizenship.
"We will live up to our promises to them," Foreign Secretary Dominic Raab told parliament.
That move has infuriated Beijing, which says Britain promised not to grant full citizenship rights to Hongkongers ahead of the 1997 handover.
"If the British side makes unilateral changes to the relevant practice, it will breach its own position and pledges as well as international law and basic norms governing international relations," China's embassy in London said Thursday.
"We firmly oppose this and reserve the right to take corresponding measures," it added.
Australian leader Scott Morrison said he was "very actively" considering offering Hong Kongers safe haven.
Taiwan has opened an office to help Hongkongers wanting to flee, while a proposed bill in the United States offering sanctuary to city residents has received widespread bipartisan support.
Beijing says the law is needed to quell seething pro-democracy protests in Hong Kong and restore order after a year of political unrest.
But critics fear it will usher in a new era of political repression given similar laws are routinely used to crush dissent on the Chinese mainland.
The law has sent fear coursing through the city and rattled the legal community in a business hub that has built its reputation on the independence and reliability of its courts.
On July 1, the US House of Representatives agreed unanimously to seek tough sanctions on Chinese officials and Hong Kong police. The House quickly passed the act that had already passed the Senate the week prior.
Due to technical changes, the Senate will need to vote again and a senator said it could happen today.
"The Chinese regime just thinks that they can act with impunity and repressing the spirit of democracy," Speaker Nancy Pelosi said before the House passage.
"If we refuse to speak out on human rights in China because of commercial interests, we lose all moral authority to speak out for human rights any place in the world," said Washington's top elected Democrat, long a vocal proponent of human rights in China.
President Donald Trump has not said if he will sign the bill but one of his allies briefly held up the Senate version, seeking changes.
Trump publicly hesitated last year before signing another rights bill on Hong Kong which also lays out sanctions against Chinese officials for infringing on the city's autonomy.
Unlike the previous act, the new legislation would make sanctions mandatory, limiting Trump's ability to waive them. In a crucial pressure point, it would also slap sanctions on banks that conduct transactions with violators.
Beijing said Thursday it "deplores and firmly opposes" the US bill, adding that Hong Kong issues are part of China's internal affairs.
"We urge the US to grasp the reality of the situation, stop interfering in Hong Kong affairs and implementing the negative bill, otherwise we will take strong countermeasures," said foreign ministry spokesman Zhao Lijian.