US President Donald Trump has signed an order to end preferential economic treatment for Hong Kong, after China enacted a new security law there.
Hong Kong would be treated “the same as mainland China”, Mr Trump said. He also signed a law to impose sanctions on officials who cracked down on rights.
China has strongly criticised the move, vowing to take retaliatory action.
The US sees the security law as a threat to the freedoms Hong Kong has enjoyed under a 1984 agreement.
That special status was agreed between China and Hong Kong’s former colonial power, the UK, before sovereignty was returned to Beijing in 1997.
The new security law – which outlaws criticism of China’s government – is the most sweeping change to the political landscape of Hong Kong since then.
How did China respond?
China’s foreign ministry condemned the latest US moves, saying they were a “gross interference” in its domestic affairs.
In a strongly-worded statement, it said the country would also impose retaliatory sanctions against US individuals and entities to “safeguard China’s legitimate interests”.
“The US attempt to obstruct the implementation of the national security law for Hong Kong will never succeed,” the statement said.
“We urge the US side to correct its mistakes, refrain from implementing the act and stop interfering in China’s internal affairs in any way. China will firmly respond if the US goes ahead.”
What is going on with US-China relations?
Washington-Beijing ties have become increasingly frayed in recent months.
With Mr Trump facing an uphill battle for re-election this November, he and Mr Biden have accused each other of being weak on China.
On Monday, the administration condemned China’s military build-up in the South China Sea, accusing it of bullying neighbours.
Last Friday, Mr Trump told reporters on Air Force One that a “phase two” trade deal with China was in doubt because of its handling of coronavirus, which he called the “plague”.
The US also officially withdrew last week from the World Health Organization, which Mr Trump had accused of being beholden to China.
Last week, too, the Trump administration announced sanctions against Chinese politicians who it says are responsible for human rights violations against Muslim minorities in Xinjiang.