The US House of Representatives on Tuesday passed a bill sought by pro-democracy protesters in Hong Kong that aims to defend civil rights in the semi-autonomous territory.
The Hong Kong Human Rights and Democracy Act, which will now move to a similar vote in the Senate before it can become law, has drawn rare bipartisan support in a polarized Congress.
Its passage is likely to further aggravate China which has accused "external forces" of fuelling weeks of unrest in the global financial hub.
"Today we're simply urging the Chinese president and the Hong Kong Chief Executive, Carrie Lam, to faithfully honor the government's promises" that Hong Kong's rights and autonomy would be protected, Republican
Representative Chris Smith, prime sponsor of the bill, said on the House floor.
Millions have taken to the streets of Hong Kong, initially against a now-dropped bid by its leaders to allow extraditions to the authoritarian Chinese mainland.
The months-long movement has expanded into a broader pro-democracy push in the territory where activists say freedoms are being eroded by Beijing, despite a deal that outlined Hong Kong's 1997 return to China from British colonial rule.
The Hong Kong Rights and Democracy Act would end Hong Kong's special trading status with the United States unless the State Department certifies annually that city authorities are respecting human rights and the rule of law.
It also requires the US president to identify and sanction people who are responsible for the erosion of autonomy and serious abuses of human rights in Hong Kong.
"The House just sent a strong message to the people of Hong Kong: We stand with you in the fight for democracy and justice," said Ben Ray Lujan, a House Democrat.
Republican House member Mario Diaz-Balart said the Act ensures "that the special relationship with Hong Kong endures only as long as Hong Kong retains the autonomy and freedoms that justify that special relationship."
The House also approved, by a similar voice vote, a related bill to prohibit the export of certain non-lethal crowd control items such as tear gas to Hong Kong.
Amnesty International has accused the city's officers of using excessive force, although the police say they have exercised restraint.
A separate house resolution called on the Hong Kong government to begin negotiations to address the demonstrators' demands, which include universal suffrage and an independent probe into police conduct.
Prominent Hong Kong activists testified before a congressional hearing last month in support of the legislation approved by the House on Tuesday.