Police in Hong Kong have fired pepper pellets and made 360 arrests as thousands of people took to the streets in anger over national security legislation proposed by China.
Riot police dispersed crowds in the financial district and elsewhere police rounded up groups of suspected protesters, making them sit on sidewalks before searching their belongings.
Late into Wednesday evening, protesters were still cramming footpaths, chanting for full democracy and for Hong Kong to seek independence from China, saying this is now "the only way out".
A heavy police presence around the Legislative Council had earlier deterred protesters from disrupting a debate of a bill that would criminalise disrespect of the Chinese national anthem.
The bill is expected to be passed into law next month.
People of all ages took to the streets, some dressed in black, some wearing office clothes, and some hiding their identities with open umbrellas in scenes reminiscent of the unrest that shook the city last year.
"Although you're afraid inside your heart, you need to speak out," said Chang, 29, a clerk and protester dressed in black with a helmet respirator and goggles in her backpack.
Many shops, bank branches and office buildings closed early. Dozens of people were seen rounded up by riot police and made to sit on a sidewalk.
Protests have returned to the streets of Chinese-ruled Hong Kong after Beijing proposed national security laws aimed at tackling secession, subversion and terrorist activities. The planned laws could see Chinese intelligence agencies set up bases in the semi-autonomous city.
The move triggered the first big street unrest in Hong Kong in months on Sunday, with police firing tear gas and water cannon to disperse protesters.
The United States, Australia, Britain, Canada and others have expressed concerns about the legislation, widely seen as a potential turning point for China's freest city and one of the world's leading financial hubs.
Protesters in a downtown shopping mall chanted "Liberate Hong Kong! Revolution of our times" and "Hong Kong independence, the only way out", but dispersed as lookouts shouted a warning to "go shopping!" at the sight of police vans outside.
One protester was seen with a placard reading "one country, two systems is a lie", referring to the political system put in place at Britain's 1997 handover of the city to China that is meant to guarantee Hong Kong's freedoms until at least 2047.
"I'm scared ... if you don't come out today, you'll never be able to come out. This is legislation that directly affects us," said Ryan Tsang, a hotel manager.
Chinese authorities and the Beijing-backed government in Hong Kong say there is no threat to the city's high degree of autonomy and the new security laws will be tightly focused.
"It's for the long-term stability of Hong Kong and China, it won't affect the freedom of assembly and speech and it won't affect the city's status as a financial centre," Hong Kong Chief Secretary Matthew Cheung told reporters. "It would provide a stable environment for businesses."
Hong Kong's most prominent tycoon, Li Ka-shing, said in a statement security laws were within every nation's right, but Hong Kong had the "mission-critical task" to maintain trust in "one country, two systems".
Hong Kong media reported Beijing had expanded the scope of the draft security legislation to include organisations as well as individuals.
The law was being revised to cover not just behaviour or acts that endanger national security, but also activities, broadcaster RTHK and the South China Morning Post reported.
US President Donald Trump on Tuesday said the United States this week would announce a strong response to the planned security legislation for Hong Kong.
The US-China Business Council (USCBC) urged "all leaders to take those steps necessary to de-escalate tensions, promote economic recovery and the rule of law, and preserve the 'one country, two systems' principle."
Asian shares slipped over rising tensions between the United States and China. Hong Kong shares led declines with the Hang Seng falling 0.46 percent, though it kept a bit of distance from a two-month low touched on Monday.
Protesters and pro-democracy politicians say Hong Kong's National Anthem Bill, which aims to govern the use and playing of the Chinese national anthem, represents another sign of what they see as accelerating interference from Beijing.
The bill carries penalties of up to three years jail and/or fines of up to HK$50,000 ($NZ10,415) for those who insult the anthem. It also orders that primary and secondary school students in Hong Kong be taught to sing the "March of the Volunteers", along with its history and etiquette.
"As long as citizens don't disrespect the anthem law, there's no need to worry, I hope people can discuss the bill rationally," Chief Secretary Cheung said.
The anthem bill is set for a second reading on Wednesday and is expected to become law next month.