Hundreds of thousands of protesters marched through Hong Kong on Sunday to voice their opposition to legislation that would allow people to be extradited to mainland China where they could face politically charged trials.
The massive demonstration took place three days before the government's plans to bring the highly contentious bill to the full legislature in a bid to win approval by the end of the month.
Police estimated the crowd at 240,000, but organizers said more than a million took part.
The protest was one of the largest in recent Hong Kong history, underscoring fears over China's broadening footprint in the former British colony.
It appeared to be even bigger than a massive pro-democracy demonstration in 2003 against a proposed national security law, according to Associated Press journalists who covered both events.
Late on Sunday night, a group of demonstrators broke through barriers at government headquarters, where the march had ended.
The crowd briefly pushed its way into the lobby, but police used batons and pepper spray, and the protesters were moved outside. Most had dispersed by 1 a.m.
People of all ages took part in the march, some pushing strollers and others carrying canes, chanting slogans in the native Cantonese dialect in favor of greater transparency in government.
Kiwi Wong, 27, was among the crowd, a member of the younger generation that has grown up enjoying relative prosperity but also growing insecurity about what many see as an erosion of the rights Hong Kong residents have enjoyed.
"If I didn't come out now, I don't know when I would have the chance to express my opinion again," Wong said.
"Because now we've got to this stage, if you don't come out to try to do what you can, then it will end up too late, you won't be able to say or do anything about it."
Alex Ng, a 67-year-old retiree in the protest, said: "I think that there was never any public consultation about this law, and there are a lot of uncertainties."
Hong Kong's leader, Carrie Lam, has pushed forward with the legislation despite widespread criticism from human rights and business groups.
The amendments have been criticized as eroding Hong Kong's judicial independence by making it easier to send criminal suspects to mainland China, where they could face vague national security charges and unfair trials.
"What can we do to get Carrie Lam to listen to us, how many people have to come out to make her reconsider listening to the public?" said Miu Wong, a 24-year-old office worker among the protesters.
Tommy Lam, a 29-year-old who is working on his master's degree, said: "All these people coming out and marching sends a definite message. If the government doesn't listen, there will be tension."
The Hong Kong government said in a statement late on Sunday that it respected the right of its opponents to protest.
"We acknowledge and respect that people have different views on a wide range of issues," the statement said.
"The procession today is an example of Hong Kong people exercising their freedom of expression within their rights as enshrined in the Basic Law and the Hong Kong Bill of Rights Ordinance."
Hong Kong was guaranteed the right to retain its own social, legal and political systems for 50 years following its handover from British to Chinese rule in 1997, the so-called "one country, two systems" framework.
However, China's ruling Communist Party has been seen as increasingly reneging on that agreement by forcing through unpopular legal changes.
Hong Kong currently limits extraditions to jurisdictions with which it has existing extradition agreements or to others on an individual basis under a law passed before 1997.
China was excluded because of concerns over its poor record on legal independence and human rights.
In recent years, mainland authorities have gone after opponents by accusing them of dubious crimes such as tax evasion, deepening worries among critics and others.