China threatens 'countermeasures' after Trump signs bills supporting Hong Kong protesters

China on Thursday accused the US of harbouring "sinister intentions" and warned of "countermeasures" after President Donald Trump signed a bill supporting pro-democracy protesters in Hong Kong.

The Chinese Foreign Ministry's statements came just hours after Trump signed the Hong Kong Human Rights and Democracy Act of 2019 into law.

The bill would require the State Department to certify once a year that Hong Kong is sufficiently autonomous to retain its special US trading consideration a status that helps its economy.

Reacting to Trump's move, the Chinese Foreign Ministry said: "This is a severe interference in Hong Kong's affairs, which are China's internal affairs".

"It is also in serious violation of international law and basic norms governing international relations. The Chinese government and people firmly oppose such stark hegemonic acts," the statement said.

"The nature of this is extremely abominable, and harbours absolutely sinister intentions," the statement said.

"This act will only further expose the malicious and hegemonic nature of US intentions to the Chinese people, including our Hong Kong compatriots. And the Chinese people will only stand in greater solidarity. The US attempts are bound to fail," it said.

But at the same time, it sought to reassure that China would implement the 'one country two system' formula under which Hong Kong was handed over to China by Britain in 1997.

Hong Kong is a semi-autonomous territory which operates under the 'one country, two systems' principle a structure that grants the city's citizens some degree of financial and legal independence from the mainland.

Hong Kong has been shaken by massive, sometimes violent, protests initially organised to oppose a now-suspended bill that would have allowed extraditions to mainland China. These protests have now turned into a wider movement for democratic reforms.

"The Chinese government is determined in opposing foreign interference in Hong Kong's affairs," the statement said.

"We are determined in implementing the 'one country, two systems' principle and safeguarding national sovereignty, security and development interests. We urge the US not to continue going down the wrong path, or China will take countermeasures, and the US must bear all consequences," it said.

The legislation came at a time when China and the US reached an advanced stage of negotiations to sign phase one agreement to end a trade war between the two world's largest economies.