Hong Kong police have made their first arrests under a new national security law, after issuing warnings to pro-democracy protesters who had gathered at a shopping centre on Wednesday.
Mass detentions followed on a range of suspected offences as protests continued into the evening, which involved clashes between demonstrators and police.
The protests and unrest come on the 23rd anniversary of the city's handover from the UK to China.
Updating arrest figures several times, the security forces said on social media that by late evening they had made "around 370 arrests". Earlier police said those detained were held on various charges, from unlawful assembly to violation of the national security law. Ten people were arrested in connection with the new measure, they said.
The European Union has reiterated its "grave concerns about this law", following earlier criticism from EU leaders and human rights groups.
The British government has said it intends to give Hong Kong residents a path to UK residency and citizenship, saying it wants to uphold its duty to the former British colony.
Punishment for violations of the new law can go as far as life in prison. But China has again defended the legislation, insisting that the situation in Hong Kong is its own internal business.
'Around 370' arrests
Protests have taken place in Hong Kong on the anniversary of the handover for many years, but police refused permission this year, citing virus concerns and the probability of violence.
The first demonstrator to be detained was arrested for carrying a flag calling for Hong Kong independence.
The man was intercepted by police in the city’s Causeway Bay shopping district, as police used pepper spray to break up the protest. Water cannon was also used to disperse the crowd.
Police later arrested a woman for holding up a sign displaying the British flag and calling for Hong Kong's independence. Further arrests then followed.
The contentious new law approved by China came into effect on Tuesday night. It allows authorities to crack down on subversive and secessionist activity in Hong Kong, sparking fears that it would be used to curb opposition voices in the semi-autonomous territory.
China's senior official in charge of Hong Kong affairs defended the new law on Wednesday. Zhang Xiaoming told a news conference it was necessary to correct the "deviation" in the understanding of the "one country, two systems" in Hong Kong.
"The central government has demonstrated enough political tolerance to adopt the 'one country, two systems, in Hong Kong. You (the oppositions) can exist in the long run and have political dissents, including opposition to the government policies," he said, adding that people were free to criticise the ruling Communist Party but could not "turn these into actions".
- "What China is doing today is exactly what... any other country in the world would ask as a minimum." Watch the interview with Victor Gao, former translator for ex-Chinese leader Deng Xiaoping's, in the video player above.
Even shouting slogans or holding up banners or flags calling for the city's independence is a violation of the law, regardless of whether violence is used.
It also covers terrorist activities, as well as foreign intervention in the city's affairs. It follows months of anti-government protests that at times descended into violence last year.
EU issues fresh condemnation
There was fresh condemnation from the EU on Wednesday in a communique from the European Council, representing leaders and governments.
"The European Union is concerned that the law risks seriously undermining the high degree of autonomy of Hong Kong, and having a detrimental effect on the independence of the judiciary and the rule of law," the statement said.
It urged China to avoid any act which undermines Hong Kong’s legal autonomy, including over human rights. The European Union's leadership said on Tuesday that it "deplored " the adoption of the law.
The security measure has met with strong opposition within Hong Kong and condemnation from former colonial ruler Britain, the US, the European Union and others.
Human rights groups have warned the law could target opposition politicians seen as insufficiently loyal to Beijing for arrest or disqualification from running in September elections for the Legislative Council.
Amnesty International described the legislation as "the greatest threat to human rights in the city's recent history".
Earlier on Wednesday Zhang Xiaoming, the official Chinese spokesman, lambasted the Western reaction, saying the new law "did not concern" foreign countries and accusing those who were considering sanctions of thinking like "bandits".
"We haven't provoked you. What gives you the right to be aggressive with us?" he told reporters.
China decided to use the National People's Congress to enact the legislation after opposition within Hong Kong's Legislative Council and within society as a whole made it impossible to pass at the local level.
The law is seen as the most significant erosion to date of Hong Kong's British-style rule of law and high degree of autonomy that China promised Hong Kong would enjoy at least through 2047 under the ``"one country, two systems'' framework.