Various observers told the BBC protests are unlikely to stop the extradition bill because Beijing has become more domineering under Communist Party chief Xi Jinping and China's economy has grown stronger, making it less anxious about the economic fallout from heavy-handed actions taken in Hong Kong.
Critics have accused Lam of ignoring widespread opposition to the extradition law amendments.
"I have not received any instruction or mandate from Beijing to do this bill", she told reporters.
She also argues that the law meets global standards for human rights, and that only serious crimes that carry sentences above seven years will be considered. China has been exerting its influence, reaching across the border to abduct dissidents taking refuge in Hong Kong. The protesters used metal barricades as clubs and threw bottles at the police, who fought back with batons and pepper spray.
Several thousand people turned out despite heavy rain.
There was a heavy police presence on downtown streets deep into the night. Hong Kong's top political leader is not elected by ordinary voters but by a 1,200-strong election committee accountable to Beijing.
It will also allow staff to participate.
The city's major student unions said they would boycott classes to attend the rallies, while a string of other prominent unions in the transport, social work and teaching sectors either followed suit or encouraged members to attend.
After the largely peaceful protest, a number of protesters clashed with police outside the LegCo building, leading to injuries and arrests.
But the record crowds have failed to sway chief executive Carrie Lam who has rejected calls to withdraw or delay the bill and warned opponents against committing "radical acts".
Journalist, teacher get caught up in YouTube's struggles with hate speech
Maza himself said YouTube has normalized hate speech "by treating it like a part of regular political discourse". YouTube has updated its hate speech policies to prohibit videos with white supremacy and neo-Nazi viewpoints.
What are the proposed changes?
Hong Kong now limits such extraditions to jurisdictions with which it has existing extradition agreements or to others on an individual basis under a law passed before 1997. The measure is also only applicable on a case-by-case basis.
Hong Kong Bar Association Chair Philip Dykes said a lack of faith in Beijing remained a crucial issue.
Many young Hong Kongers have hardened their attitudes toward China after failing to win any concessions since the 2014 protests and the violence after Sunday's rally fits a now familiar pattern.
Another State Department official said Ortagus was referring the United States-Hong Kong Policy Act of 1992, which establishes the legal framework by which Washington accords Hong Kong special treatment distinct from the rest of China for purposes of USA domestic law. The insurance of a fair trial will not be written into the bill, according to lawmakers.
"The people of Hong Kong want to protect our freedom, our freedom of speech, our rule of law, our judicial system, and also our economic foundation, which is welcome to worldwide investors", activist Lee Cheuk-yan, a former Hong Kong legislator, told AP.
What are the wider fears about Beijing's influence on Hong Kong?
Rep. Eliot Engel (D-N.Y.), in a statement on June 10, said the proposed bill would "do serious damage to the rule of law and self-governance in Hong Kong".
Beijing retains control of foreign and defence affairs, and visas or permits are required for travel between Hong Kong and the mainland.
The Catholic Diocese of Hong Kong called on the government not to pass the bill "hurriedly" and urged all Christians to pray for the former colony.