Hong Kong's radical demonstrators have repeatedly used extremely risky tools to attack police officers, which already constitutes a serious violent crime, and also shows the first signs of terrorism emerging.
Still, scores of protesters were arrested, sometimes after being beaten with batons and bloodied by police. Protesters hurled bricks at officers and ignored warnings to leave before tear gas was deployed in the Sham Shui Po area, police said, calling a march there an "unauthorised assembly".
The United States flag has become a frequent sight at protests, as some called for Washington to, among other actions, pass the Hong Kong Human Rights and Democracy Act, a law that would reaffirm U.S. commitment to upholding Hong Kong's limited democracy and rule of law.
"Hong Kong's radical demonstrators have repeatedly used extremely risky tools to attack police officers, which already constitutes a serious violent crime, and also shows the first signs of terrorism emerging", said Yang Guang, spokesman for the Hong Kong and Macao Affairs Office of the State Council.
Demonstrators say they are fighting the erosion of the "one country, two systems" arrangement enshrining some autonomy for Hong Kong when China took it back from Britain in 1997.
Tang said that on August 11, some people turned a deaf ear to the police's objection and got involved in unauthorized rallies.
"The protesters actually support that", Wong said about United States support for the movement, noting that protesters wave American flags alongside British colonial-era and independent Hong Kong flags.
Volleys of tear gas were fired inside at least two mass transit stations, exposing both protesters and bystanders to the noxious gas.
Protesters have called for an inquiry into the actions of the police.
All passenger flights in and out of Hong Kong were cancelled Monday afternoon after thousands of pro-democracy protesters flooded the city's airport to denounce police violence, stranding many Thai nationals.More news: New Immigration Rule Could Impact Half A Million Mass. Residents
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"We have been completely abandoned by the airport staff", they said.
Mass protests at Hong Kong's global airport have forced flight cancellations to and from Australia.
The Royal Thai Consulate-General in Hong Kong is advising Thai nationals now in Hong Kong to time their trips to the airport accordingly. Meanwhile despite carrying out regular press briefings, the Hong Kong government has at times appeared at a loss as to how to engage with residents and protesters.
Hundreds of people returned on Monday to the scene of some of the clashes to protest against the use of force.
Resident-led group Parents United of Hong Kong also issued an online statement calling the police's actions on August 11 "cold-blooded violence".
They also argued the bill would give China more control over Hong Kong.
This weekend was the 10th weekend in a row that demonstrators have protested a proposed new bill that would allow extradition to mainland China from Hong Kong.
Demonstrators were also angered by the use of undercover police, dressed as protesters.
Chinese officials have also appealed to Hong Kongers directly to condemn the violent protests, in an apparent attempt to split the movement.