Protestors clashed with police in Hong Kong in the early hours of Monday (June 10) as several hundred demonstrators tried to force their into the city's parliament.
Images show police waving batons and deploying a water cannon.
The scuffles came hours after hundreds of thousands of protesters had marched peacefully through the city to protest against new potential law, which would allow Beijing to extradite Hong Kong suspects to mainland China for trial.
PROTESTERS CHANTING (English): "NO CHINA EXTRADITION!"
And in turn raised fears among activists about China's grip on the semi-autonomous island.
The demonstrations were the biggest against the Chinese government in at least 15 years.
Reuters correspondent James Pomfret spent the day in the streets.
(SOUNDBITE) (ENGLISH) REUTERS CORRESPONDENT, JAMES POMFRET, SAYING:
"People here aren't just your hard core protesters you have ordinary citizens. You have fathers, mothers, kids and they don't feel comfortable if the law is enacted because it will allow China in effect to impose or part of its legal system to encroach into Hong Kong for the first time ever. And this march could be a turning point in finally persuading the authorities to either postpone or scrap it."
The bill will be debated on Wednesday (June 12) and could come into effect at the end of this month.
Hong Kong's leader, Carrie Lam, has tweaked the proposal, but refused to scrap the bill - prompting calls for her resignation.
(SOUNDBITE) (ENGLISH) REUTERS CORRESPONDENT, JAMES POMFRET.
"It's such an overwhelmingly large number of people that it will be very difficult for Hong Kong's leader, Carrie Lam, and the Beijing communist leaders to ignore this."
Senior judges in Hong Kong have expressed their concern over a lack of trust in Chinese courts, and human rights groups are worried about the use of torture and lack of judicial rights on the mainland.