Hong Kong police fired volleys of tear gas and a water cannon in a popular shopping district as thousands took to the streets on Sunday to march against China’s proposed tough national security legislation for the city.

Pro-democracy supporters in Hong Kong have sharply criticised China’s proposal to enact a national security law that would ban secessionist and subversive activity, as well as foreign interference, in the semi-autonomous territory.

Critics say it goes against the “one country, two systems” framework that promises the city freedoms not found in mainland China.

On Sunday afternoon, crowds of protesters dressed in black gathered in Causeway Bay, a popular shopping district, to protest against the proposed legislation.

Protesters chanted slogans “Stand with Hong Kong”, “Liberate Hong Kong” and “Revolution of our times”.

The protest was a continuation of a months-long pro-democracy movement in Hong Kong that began last year and has at times descended into violence between police and protesters.

Police raised blue flags, warning protesters to disperse, before firing multiple rounds of tear gas. They later fired a water cannon at the protesters.

At least 180 people were arrested, mostly on charges of unlawful assembly, police said.

They also said in a separate post that protesters threw bricks and splashed unidentified liquid at officers, injuring at least four members of the police’s media liaison team.

They warned that such behaviour is against the law and that police would pursue the matter.

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Hong Kong riot police fire tear gas as hundreds of protesters march along a street during a pro-democracy protest against Beijing’s national security legislation (Vincent Yu/AP)

Earlier in the afternoon, prominent activist Tam Tak-chi was arrested during the protests for what police said was an unauthorised assembly.

Mr Tam said he was giving a “health talk” and was exempt from social-distancing measures that prohibit gatherings of more than eight people.

The bill that triggered Sunday’s rally was submitted at China’s national legislative session on Friday and is expected to be passed on May 28.

It would bypass Hong Kong’s legislature and allow the city’s government to set up mainland agencies in the city that would make it possible for Chinese agents to arbitrarily arrest people for activities deemed to be pro-democracy.

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Protesters set up blockades during a protest against Beijing’s national security legislation in Hong Kong (Kin Cheung/AP)

Speaking on the sidelines of the annual session of China’s ceremonial parliament in Beijing, Chinese Foreign Minister Wang Yi said on Sunday that Hong Kong affairs were an internal matter for China, and that “no external interference will be tolerated”.

“Excessive unlawful foreign meddling in Hong Kong affairs has placed China’s national security in serious jeopardy,” Mr Wang said, adding that the proposed legislation “does not affect the high degree of autonomy in Hong Kong”.

“It does not affect the rights and freedoms enjoyed by Hong Kong residents. And it does not affect the legitimate rights and interests of foreign investors in Hong Kong,” he said.

US Secretary of State Mike Pompeo has called the move “a death knell for the high degree of autonomy” that Beijing had promised Hong Kong.

Chris Patten, the last British governor of Hong Kong prior to its handover to China in 1997, condemned what he called “a new Chinese dictatorship”.

“I think the Hong Kong people have been betrayed by China, which has proved once again that you can’t trust it further than you can throw it,” he said in an interview with The Times.

US president Donald Trump’s national security adviser, Robert O’Brien, said it appeared China was violating the 1984 treaty.

“And I can’t see how Hong Kong remains the Asian financial centre if the Chinese Communist Party goes through and implements this national security law and takes over Hong Kong,” Mr O’Brien said on CBS’s Face The Nation programme.

“That would be a tragedy for the people of Hong Kong, but it will also be very bad for China.”

Bernard Chan, a top-level Hong Kong politician and delegate to the National People’s Congress in Beijing, defended national security legislation pushed by China, saying it was written into Hong Kong’s Basic Law — the city’s mini-constitution — but never enacted.

Mr Chan expressed concern that Hong Kong will inevitably face economic hardship given trade frictions between the US and China.

“I think we are definitely the collateral damage being dragged into this thing. But then, I don’t think there’s any alternatives,” Mr Chan said.

“But with or without this law, honestly, the US and China will always going to be continuing this loggerhead for quite some time to come,” he said.

“China will remain as a threat to the US in terms of the … world economic dominance.”