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.