US President Donald Trump says his administration will start revoking a range of special treatments given to Hong Kong. It comes after China decided to introduce new security legislation in the territory as a crackdown on anti-government activities.

Trump made the announcement at a news conference on Friday. China's congress approved the security legislation plan on Thursday.

Trump said Hong Kong is no longer sufficiently autonomous to warrant preferential treatment. He accused Beijing of replacing its "one country, two systems" framework with "one country, one system."

He said the move will affect the full range of agreements between the US and Hong Kong, from extradition of criminals to export controls.

Trump indicated that steps will be taken to sanction officials in mainland China and Hong Kong who are deemed to be involved in eroding the territory's autonomy.

Trump also hinted at plans to further limit Chinese firms' activities in the United States.

China maintains the new security legislation for Hong Kong is an internal affair, and is expected to react sharply to Washington's move.

The president also announced that the United States will terminate its relationship with the World Health Organization, which he says is too "China-centric".

He said funds for the WHO will be redirected to other organizations.